Steven A. Cummer

Research Themes

Metamaterials

Research Interests

Theoretical and experimental electromagnetic problems related to geophysical remote sensing and engineered electromagnetic materials.

Bio

Dr. Steven Cummer received his Ph.D. in Electrical Engineering from Stanford University in 1997 and prior to joining Duke University in 1999 he spent two years at NASA Goddard Space Flight Center as an NRC postdoctoral research associate. Awards he has received include a National Science Foundation CAREER award and a Presidential Early Career Award for Scientists and Engineers (PECASE) in 2001. His current work is in a variety of theoretical and experimental electromagnetic problems related to geophysical remote sensing and engineered electromagnetic materials.

Education

• B.S.E.E. Stanford University, 1991
• M.S.E.E. Stanford University, 1993
• Ph.D. Stanford University, 1997

Positions

• William H. Younger Distinguished Professor of Engineering
• Associate Chair of Faculty Affairs in the Department of Electrical and Computer Engineering
• Professor of Electrical and Computer Engineering
• Bass Fellow

Awards, Honors, and Distinctions

• Stansell Family Distinguished Research Award. Pratt School of Engineering. 2018
• Fellow. Institute for Electrical and Electronics Engineers. 2011
• Presidential Early Career Awards for Scientists and Engineers. President of the United States of America. 2001

Courses Taught

• ECE 891: Internship
• ECE 590: Advanced Topics in Electrical and Computer Engineering
• ECE 574: Waves in Matter
• ECE 392: Projects in Electrical and Computer Engineering
• ECE 391: Projects in Electrical and Computer Engineering
• ECE 270L9: Fields and Waves: Fundamentals of Information Propagation (Lab)
• ECE 270DL: Fields and Waves: Fundamentals of Information Propagation
• ECE 110L: Fundamentals of Electrical and Computer Engineering
• ECE 110L9: Fundamentals of Electrical and Computer Engineering - Lab

Publications

• Martí-Sabaté M, Li J, Djafari-Rouhani B, Cummer SA, Torrent D. Observation of two-dimensional acoustic bound states in the continuum. Communications Physics. 2024 Dec 1;7(1).
• Dong HW, Shen C, Liu Z, Zhao SD, Ren Z, Liu CX, et al. Inverse design of phononic meta-structured materials. Materials Today. 2024 Nov 1;80:824–55.
• Pu Y, Cummer SA. Continuous Initial Breakdown Development of In-Cloud Lightning Flashes. Journal of Geophysical Research: Atmospheres. 2024 Oct 28;129(20).
• Malla H, Guo Y, Hare BM, Cummer S, Malagón-Romero A, Ebert U, et al. Calculating Radio Emissions of Positive Streamer Phenomena Using 3D Simulations. Journal of Geophysical Research: Atmospheres. 2024 Oct 28;129(20).
• Lyu F, Qin Z, Cummer SA, Zheng Y, Jiang S, Zheng T, et al. Source Altitude of Energetic In-Cloud Pulses Inside Thunderstorms and Implication for the Intrinsic Brightness of Terrestrial Gamma-Ray Flashes. Geophysical Research Letters. 2024 Oct 28;51(20).
• Østgaard N, Mezentsev A, Marisaldi M, Grove JE, Quick M, Christian H, et al. Flickering gamma-ray flashes, the missing link between gamma glows and TGFs. Nature. 2024 Oct;634(8032):53–6.
• Marisaldi M, Østgaard N, Mezentsev A, Lang T, Grove JE, Shy D, et al. Highly dynamic gamma-ray emissions are common in tropical thunderclouds. Nature. 2024 Oct;634(8032):57–60.
• Bjørge-Engeland I, Østgaard N, Sarria D, Marisaldi M, Mezentsev A, Fuglestad A, et al. Evidence of a New Population of Weak Terrestrial Gamma-Ray Flashes Observed From Aircraft Altitude. Geophysical Research Letters. 2024 Sep 16;51(17).
• Chaffin JM, Smith DM, Lapierre J, Cummer S, Ortberg J, Sunjerga A, et al. Mountaintop Gamma Ray Observations of Three Terrestrial Gamma-Ray Flashes at the Säntis Tower, Switzerland With Coincident Radio Waveforms. Journal of Geophysical Research: Atmospheres. 2024 Jan 28;129(2).
• Pu Y, Cummer SA. Imaging Step Formation in In-Cloud Lightning Initial Development With VHF Interferometry. Geophysical Research Letters. 2024 Jan 16;51(1).
• Stohn A, Guo S, Hernandez G, Wiley B, Cummer S, Gehm M. Design and solution-based testing of a synthetic aerosol particle with asymmetric scattering behavior. In: Proceedings of SPIE - The International Society for Optical Engineering. 2024.
• Cummer SA. Transformation Acoustics. In: Springer Series in Materials Science. 2024. p. 213–35.
• Inchin PA, Bhatt A, Cummer SA, Eckermann SD, Harding BJ, Kuhl DD, et al. Multi-Layer Evolution of Acoustic-Gravity Waves and Ionospheric Disturbances Over the United States After the 2022 Hunga Tonga Volcano Eruption. AGU Advances. 2023 Dec 1;4(6).
• Chaffin JM, Pu Y, Smith DM, Cummer S, Splitt M. Determining a Lower Limit of Luminosity for the First Satellite Observation of a Reverse Beam Terrestrial Gamma Ray Flash Associated With a Cloud to Ground Lightning Leader. Journal of Geophysical Research: Atmospheres. 2023 Sep 27;128(18).
• Peng X, Li J, Cummer SA. Ultra-broadband low-frequency high-efficiency acoustic energy harvesting with metamaterial-enhanced loudspeakers. Applied Physics Letters. 2023 Aug 14;123(7).
• Pu Y, Cummer SA, Lyu F, Zheng Y, Briggs MS, Lesage S, et al. Unsupervised Clustering and Supervised Machine Learning for Lightning Classification: Application to Identifying EIPs for Ground-Based TGF Detection. Journal of Geophysical Research: Atmospheres. 2023 May 16;128(9).
• Shen C, Rohde C, Cushing CW, Li J, Tan ZJ, Du H, et al. Anisotropic Metallic Microlattice Structures for Underwater Operations. Advanced Engineering Materials. 2023 Mar 1;25(6).
• Ji J, Li J, Cummer SA, Jing Y. Ultra-sparse near-perfect sound absorbers. JASA express letters. 2023 Mar;3(3):034001.
• Shen L, Tai J, Crivoi A, Li J, Cummer S, Fan Z. Self-stabilizing three-dimensional particle manipulation via a single-transducer acoustic tweezer. Applied Physics Letters. 2023 Feb 27;122(9).
• Krushynska AO, Torrent D, Aragón AM, Ardito R, Bilal OR, Bonello B, et al. Emerging topics in nanophononics and elastic, acoustic, and mechanical metamaterials: an overview. Nanophotonics (Berlin, Germany). 2023 Feb;12(4):659–86.
• Zhang M, Lu G, Huang H, Cheng Z, Chen Y, Cummer SA, et al. Automatic recognition of tweek atmospherics and plasma diagnostics in the lower ionosphere with the machine learning method. Earth and Planetary Physics. 2023 Jan 1;7(3):407–13.
• Martí-Sabaté M, Li J, Djafari-Rouhani B, Cummer S, Torrent D. Quasi-Bound States in the Continuum for Acoustic and Elastic Waves. In: International Conference on Metamaterials, Photonic Crystals and Plasmonics. 2023. p. 514.
• Dong H-W, Shen C, Zhao S-D, Qiu W, Zheng H, Zhang C, et al. Achromatic metasurfaces by dispersion customization for ultra-broadband acoustic beam engineering. National science review. 2022 Dec;9(12):nwac030.
• Huang A, Cummer SA, Pu Y, Chanrion OA, Neubert T, Reglero V, et al. Transition in Optical and Radio Features During the Early Development of Negative Intracloud Leader. Geophysical Research Letters. 2022 Nov 28;49(22).
• Huang L, Jia B, Pilipchuk AS, Chiang Y, Huang S, Li J, et al. General Framework of Bound States in the Continuum in an Open Acoustic Resonator. Physical Review Applied. 2022 Nov 1;18(5).
• Boggs LD, Mach D, Bruning E, Liu N, van der Velde OA, Montanyá J, et al. Upward propagation of gigantic jets revealed by 3D radio and optical mapping. Science advances. 2022 Aug;8(31):eabl8731.
• Berge N, Celestin S, Garnung MB, Xu W, Marshall RA, Cummer SA. Modeling Low-Frequency Radio Emissions From Terrestrial Gamma Ray Flash Sources. Journal of Geophysical Research: Atmospheres. 2022 Mar 16;127(5).
• Pu Y, Liu N, Cummer SA. Quantification of Electric Fields in Fast Breakdown During Lightning Initiation From VHF-UHF Power Spectra. Geophysical Research Letters. 2022 Mar 16;49(5).
• Li J, Jing Y, Cummer SA. Nonreciprocal coupling in space-time modulated systems at exceptional points. Physical Review B. 2022 Mar 1;105(10).
• Granger J, Cummer SA, Lohmann KJ, Johnsen S. Environmental sources of radio frequency noise: potential impacts on magnetoreception. Journal of comparative physiology A, Neuroethology, sensory, neural, and behavioral physiology. 2022 Jan;208(1):83–95.
• Li J, Crivoi A, Peng X, Shen L, Pu Y, Fan Z, et al. Three dimensional acoustic tweezers with vortex streaming. Communications Physics. 2021 Dec 1;4(1).
• Li J, Shen C, Huang TJ, Cummer SA. Acoustic tweezer with complex boundary-free trapping and transport channel controlled by shadow waveguides. Science advances. 2021 Aug;7(34):eabi5502.
• Wang Y, Lu G, Cummer SA, Lucena F, Cohen MB, Ren H, et al. Ground Observation of Negative Sprites Over a Tropical Thunderstorm as the Embryo of Hurricane Harvey (2017). Geophysical Research Letters. 2021 Jul 28;48(14).
• Lyu F, Cummer SA, Krehbiel PR, Rison W, Bruning EC, Rutledge SA. A Distinct Class of High Peak-Current Lightning Pulses Over Mountainous Terrain in Thunderstorms. Geophysical Research Letters. 2021 Jul 28;48(14).
• Huang A, Yang J, Cummer SA, Lyu F, Liu N. Examining the Capacity of Hurricane Matthew (2016) in Spawning Halo/Sprite-Producible Lightning Strokes During Its Lifetime. Journal of Geophysical Research: Atmospheres. 2021 Jul 27;126(14).
• Lyu F, Cummer SA, Briggs M, Smith DM, Mailyan B, Lesage S. Terrestrial Gamma-Ray Flashes Can Be Detected With Radio Measurements of Energetic In-Cloud Pulses During Thunderstorms. Geophysical Research Letters. 2021 Jun 16;48(11).
• Pu Y, Cummer SA, Liu N. VHF Radio Spectrum of a Positive Leader and Implications for Electric Fields. Geophysical Research Letters. 2021 Jun 16;48(11).
• Østgaard N, Cummer SA, Mezentsev A, Luque A, Dwyer J, Neubert T, et al. Simultaneous Observations of EIP, TGF, Elve, and Optical Lightning. Journal of Geophysical Research: Atmospheres. 2021 Jun 1;126(11).
• Ren H, Lu G, Cummer SA, Peng KM, Lyons WA, Liu F, et al. Comparison Between High-Speed Video Observation of Sprites and Broadband Sferic Measurements. Geophysical Research Letters. 2021 May 28;48(10).
• Shen C, Lu S, Tian Z, Yang S, Cardenas JA, Li J, et al. Electrically Tunable Surface Acoustic Wave Propagation at MHz Frequencies Based on Carbon Nanotube Thin-Film Transistors. Advanced Functional Materials. 2021 May 1;31(18).
• Zhang H, Lu G, Lyu F, Xiong S, Ahmad MR, Yi Q, et al. On the Terrestrial Gamma-Ray Flashes Preceding Narrow Bipolar Events. Geophysical Research Letters. 2021 Apr 28;48(8).
• Huang A, Cummer SA, Pu Y. Lightning Initiation From Fast Negative Breakdown is Led by Positive Polarity Dominated Streamers. Geophysical Research Letters. 2021 Apr 28;48(8).
• Lyu F, Cummer SA, Chen M, Qin Z, Lyu W, Sun J. Three-dimensional mapping of two coincident flashes - An upward positive flash triggered by the in-cloud activity of a downward negative flash. Atmospheric Research. 2021 Mar 1;250.
• Cushing CW, Wilson PS, Haberman MR, Shen C, Li J, Cummer SA, et al. Characterization of an underwater metamaterial made of aluminum honeycomb panels at low frequencies. The Journal of the Acoustical Society of America. 2021 Mar;149(3):1829.
• Wang Y, Lu G, Peng KM, Ma M, Cummer SA, Chen AB, et al. Space-Based Observation of a Negative Sprite With an Unusual Signature of Associated Sprite Current. Journal of Geophysical Research: Atmospheres. 2021 Feb 27;126(4).
• Peng X, Li J, Shen C, Cummer SA. Efficient scattering-free wavefront transformation with power flow conformal bianisotropic acoustic metasurfaces. Applied Physics Letters. 2021 Feb 8;118(6).
• Mailyan B, Stanbro M, Briggs MS, Cummer S, Dwyer JR, Roberts OJ, et al. Radio Frequency Emissions Associated With Multi-Pulsed Terrestrial Gamma-Ray Flashes. Journal of Geophysical Research: Space Physics. 2021 Feb 1;126(2).
• Tian Z, Shen C, Li J, Reit E, Gu Y, Fu H, et al. Correction: Programmable Acoustic Metasurfaces (Advanced Functional Materials, (2019), 29, (1808489), 10.1002/adfm.201808489). Advanced Functional Materials. 2020 Dec 1;30(50).
• Qin Z, Chen M, Lyu F, Cummer SA, Gao Y, Liu F, et al. Prima Facie Evidence of the Fast Impact of a Lightning Stroke on the Lower Ionosphere. Geophysical Research Letters. 2020 Nov 16;47(21).
• Gu Y, Chen C, Rufo J, Shen C, Wang Z, Huang P-H, et al. Acoustofluidic Holography for Micro- to Nanoscale Particle Manipulation. ACS nano. 2020 Nov;14(11):14635–45.
• Tilles JN, Krehbiel PR, Stanley MA, Rison W, Liu N, Lyu F, et al. Radio Interferometer Observations of an Energetic in-Cloud Pulse Reveal Large Currents Generated by Relativistic Discharges. Journal of Geophysical Research: Atmospheres. 2020 Oct 27;125(20).
• Li J, Song A, Cummer SA. Bianisotropic Acoustic Metasurface for Surface-Wave-Enhanced Wavefront Transformation. Physical Review Applied. 2020 Oct 8;14(4).
• Fu Y, Shen C, Zhu X, Li J, Liu Y, Cummer SA, et al. Sound vortex diffraction via topological charge in phase gradient metagratings. Science advances. 2020 Oct;6(40):eaba9876.
• Zhang H, Lu G, Lyu F, Ahmad MR, Qie X, Cummer SA, et al. First Measurements of Low-Frequency Sferics Associated With Terrestrial Gamma-Ray Flashes Produced by Equatorial Thunderstorms. Geophysical Research Letters. 2020 Sep 16;47(17).
• Pu Y, Cummer SA, Huang A, Briggs M, Mailyan B, Lesage S. A Satellite-Detected Terrestrial Gamma Ray Flash Produced by a Cloud-to-Ground Lightning Leader. Geophysical Research Letters. 2020 Aug 16;47(15).
• Song A, Li J, Shen C, Chen T, Cummer SA. Switchable directional sound emission with improved field confinement based on topological insulators. Applied Physics Letters. 2020 Jul 27;117(4).
• Zhu X, Li J, Shen C, Zhang G, Cummer SA, Li L. Tunable unidirectional compact acoustic amplifier via space-time modulated membranes. Physical Review B. 2020 Jul 1;102(2).
• Qin Z, Chen M, Lyu F, Cummer SA, Zhu B, Liu F, et al. A GPU-Based Grid Traverse Algorithm for Accelerating Lightning Geolocation Process. IEEE Transactions on Electromagnetic Compatibility. 2020 Apr 1;62(2):489–97.
• Cummer SA. Indirectly Measured Ambient Electric Fields for Lightning Initiation in Fast Breakdown Regions. Geophysical Research Letters. 2020 Feb 28;47(4).
• Zhu X, Li J, Shen C, Peng X, Song A, Li L, et al. Non-reciprocal acoustic transmission via space-time modulated membranes. Applied Physics Letters. 2020 Jan 21;116(3).
• Cummer S. Data from: Indirectly measured ambient electric fields for lightning initiation in fast breakdown regions. 2020.
• Pu Y, Cummer SA. Needles and Lightning Leader Dynamics Imaged with 100–200 MHz Broadband VHF Interferometry. Geophysical Research Letters. 2019 Nov 28;46(22):13556–63.
• Song A, Li J, Peng X, Shen C, Zhu X, Chen T, et al. Asymmetric absorption in acoustic metamirror based on surface impedance engineering. Physical Review Applied. 2019 Nov 20;12(5).
• Li J, Zhu X, Shen C, Peng X, Cummer SA. Transfer matrix method for the analysis of space-time-modulated media and systems. Physical Review B. 2019 Oct 31;100(14).
• Andrews JB, Ballentine P, Cardenas JA, Lim CJ, Williams NX, Summers JB, et al. Printed electronic sensor array for mapping tire tread thickness profiles. IEEE Sensors Journal. 2019 Oct 1;19(19):8913–9.
• Cuesta F, Li J, Diaz-Rubio A, Asadchy V, Cummer S, Tretyakov S. Advanced control of invisible cavity resonators with bianisotropic metasurfaces. In: 2019 13th International Congress on Artificial Materials for Novel Wave Phenomena, Metamaterials 2019. 2019. p. X098-X100.
• van der Velde OA, Montanyà J, López JA, Cummer SA. Gigantic jet discharges evolve stepwise through the middle atmosphere. Nature communications. 2019 Sep;10(1):4350.
• Chen ABC, Chen H, Chuang CW, Cummer SA, Lu G, Fang HK, et al. On negative Sprites and the Polarity Paradox. Geophysical Research Letters. 2019 Aug 28;46(16):9370–8.
• Shen C, Zhu X, Li J, Cummer SA. Nonreciprocal acoustic transmission in space-time modulated coupled resonators. Physical Review B. 2019 Aug 6;100(5).
• Pu Y, Cummer SA, Lyu F, Briggs M, Mailyan B, Stanbro M, et al. Low Frequency Radio Pulses Produced by Terrestrial Gamma-Ray Flashes. Geophysical Research Letters. 2019 Jun 28;46(12):6990–7.
• Gerard NJ, Cui H, Shen C, Xie Y, Cummer S, Zheng X, et al. Fabrication and experimental demonstration of a hybrid resonant acoustic gradient index metasurface at 40 kHz. Applied Physics Letters. 2019 Jun 10;114(23).
• Qin Z, Cummer SA, Du Y, Chen M, Zhu B, Lyu F, et al. Potential of GPU-based grid traverse algorithm for lightning geolocation. In: 2019 11th Asia-Pacific International Conference on Lightning, APL 2019. 2019.
• Fu Y, Shen C, Cao Y, Gao L, Chen H, Chan CT, et al. Reversal of transmission and reflection based on acoustic metagratings with integer parity design. Nature communications. 2019 May;10(1):2326.
• Li J, Shen C, Zhu X, Xie Y, Cummer SA. Nonreciprocal sound propagation in space-time modulated media. Physical Review B. 2019 Apr 25;99(14).
• Shen C, Li J, Jia Z, Xie Y, Cummer SA. Nonreciprocal acoustic transmission in cascaded resonators via spatiotemporal modulation. Physical Review B. 2019 Apr 22;99(13).
• Lyu F, Cummer SA, Qin Z, Chen M. Lightning Initiation Processes Imaged With Very High Frequency Broadband Interferometry. Journal of Geophysical Research: Atmospheres. 2019 Mar 27;124(6):2994–3004.
• Qin Z, Cummer SA, Chen M, Lyu F, Du YP. A Comparative Study of the Ray Theory Model With the Finite Difference Time Domain Model for Lightning Sferic Transmission in Earth-Ionosphere Waveguide. Journal of Geophysical Research: Atmospheres. 2019 Mar 27;124(6):3335–49.
• Song A, Li J, Shen C, Peng X, Zhu X, Chen T, et al. Broadband high-index prism for asymmetric acoustic transmission. Applied Physics Letters. 2019 Mar 25;114(12).
• Tian Z, Shen C, Li J, Reit E, Gu Y, Fu H, et al. Programmable Acoustic Metasurfaces. Advanced functional materials. 2019 Mar;29(13):1808489.
• Li J, Díaz-Rubio A, Shen C, Jia Z, Tretyakov S, Cummer S. Highly Efficient Generation of Angular Momentum with Cylindrical Bianisotropic Metasurfaces. Physical Review Applied. 2019 Feb 6;11(2).
• Lu G, Zhang H, Cummer SA, Wang Y, Lyu F, Briggs M, et al. A comparative study on the lightning sferics associated with terrestrial gamma-ray flashes observed in Americas and Asia. Journal of Atmospheric and Solar-Terrestrial Physics. 2019 Feb 1;183:67–75.
• Díaz-Rubio A, Li J, Shen C, Cummer SA, Tretyakov SA. Power flow-conformal metamirrors for engineering wave reflections. Science advances. 2019 Feb;5(2):eaau7288.
• Marisaldi M, Galli M, Labanti C, Østgaard N, Sarria D, Cummer SA, et al. On the High-Energy Spectral Component and Fine Time Structure of Terrestrial Gamma Ray Flashes. Journal of Geophysical Research: Atmospheres. 2019 Jan 1;124(14):7484–97.
• Shen C, Li J, Peng X, Cummer SA. Synthetic exceptional points and unidirectional zero reflection in non-Hermitian acoustic systems. Physical Review Materials. 2018 Dec 17;2(12).
• Huang A, Lu G, Yue J, Lyons W, Lucena F, Lyu F, et al. Observations of Red Sprites Above Hurricane Matthew. Geophysical Research Letters. 2018 Dec 16;45(23):13–165.
• Li J, Shen C, Diaz-Rubio A, Tretyakov SA, Cummer SA. Bianisotropic Acoustic Metasurface for Highly Efficient Wavefront Transformation. In: 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena, METAMATERIALS 2018. 2018. p. 254–6.
• Diaz-Rubio A, Li J, Shen C, Cummer SA, Tretyakov SA. High-effcient Acoustic Anomalous Reflector Based on Power-flow Conformal Metamirror. In: 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena, METAMATERIALS 2018. 2018. p. 477–9.
• Stanbro M, Briggs MS, Roberts OJ, Cramer ES, Cummer SA, Grove JE. A Study of Consecutive Terrestrial Gamma-ray Flashes Using the Gamma-ray Burst Monitor. Journal of Geophysical Research: Space Physics. 2018 Nov 1;123(11):9634–51.
• Xie Y, Fu Y, Jia Z, Li J, Shen C, Xu Y, et al. Acoustic Imaging with Metamaterial Luneburg Lenses. Scientific reports. 2018 Nov;8(1):16188.
• Fu Y, Li J, Xie Y, Shen C, Xu Y, Chen H, et al. Compact acoustic retroreflector based on a mirrored Luneburg lens. Physical Review Materials. 2018 Oct 18;2(10).
• Lyu F, Cummer SA. Energetic Radio Emissions and Possible Terrestrial Gamma-Ray Flashes Associated With Downward Propagating Negative Leaders. Geophysical Research Letters. 2018 Oct 16;45(19):10–771.
• Lu G, Yu B, Cummer SA, Peng KM, Chen AB, Lyu F, et al. On the Causative Strokes of Halos Observed by ISUAL in the Vicinity of North America. Geophysical Research Letters. 2018 Oct 16;45(19):10–789.
• Lu G, Fan Y, Zhang H, Jiang R, Liu M, Qie X, et al. Measurement of continuing charge transfer in rocket-triggered lightning with low-frequency magnetic sensor at close range. Journal of Atmospheric and Solar-Terrestrial Physics. 2018 Oct 1;175:76–86.
• McCall M, Pendry JB, Galdi V, Lai Y, Horsley SAR, Li J, et al. Roadmap on transformation optics. Journal of Optics (United Kingdom). 2018 Jun 1;20(6).
• Bowers GS, Smith DM, Kelley NA, Martinez-McKinney GF, Cummer SA, Dwyer JR, et al. A Terrestrial Gamma-Ray Flash inside the Eyewall of Hurricane Patricia. Journal of Geophysical Research: Atmospheres. 2018 May 27;123(10):4977–87.
• Shen C, Cummer SA. Harnessing Multiple Internal Reflections to Design Highly Absorptive Acoustic Metasurfaces. Physical Review Applied. 2018 May 8;9(5).
• Shen C, Díaz-Rubio A, Li J, Cummer SA. A surface impedance-based three-channel acoustic metasurface retroreflector. Applied Physics Letters. 2018 Apr 30;112(18).
• Li J, Shen C, Díaz-Rubio A, Tretyakov SA, Cummer SA. Systematic design and experimental demonstration of bianisotropic metasurfaces for scattering-free manipulation of acoustic wavefronts. Nature communications. 2018 Apr;9(1):1342.
• Shen C, Xie Y, Li J, Cummer SA, Jing Y. Acoustic metacages for sound shielding with steady air flow. Journal of Applied Physics. 2018 Mar 28;123(12).
• Liu F, Zhu B, Lu G, Qin Z, Lei J, Peng KM, et al. Observations of Blue Discharges Associated With Negative Narrow Bipolar Events in Active Deep Convection. Geophysical Research Letters. 2018 Mar 28;45(6):2842–51.
• Lyu F, Cummer SA, Krehbiel PR, Rison W, Briggs MS, Cramer E, et al. Very High Frequency Radio Emissions Associated With the Production of Terrestrial Gamma-Ray Flashes. Geophysical Research Letters. 2018 Feb 28;45(4):2097–105.
• Jia Z, Li J, Shen C, Xie Y, Cummer SA. Systematic design of broadband path-coiling acoustic metamaterials. Journal of Applied Physics. 2018 Jan 14;123(2).
• Mezentsev A, Lehtinen N, Østgaard N, Pérez-Invernón FJ, Cummer SA. Spectral Characteristics of VLF Sferics Associated With RHESSI TGFs. Journal of geophysical research Atmospheres : JGR. 2018 Jan;123(1):139–59.
• Fu Y, Xu Y, Chen H, Cummer SA. Coherent perfect absorption and laser modes in a cylindrical structure of conjugate metamaterials. New Journal of Physics. 2018 Jan 1;20(1).
• Singh R, Maurya AK, Chanrion O, Neubert T, Cummer SA, Mlynarczyk J, et al. Assessment of Unusual Gigantic Jets observed during the Monsoon season: First observations from Indian Subcontinent. Scientific reports. 2017 Nov;7(1):16436.
• Fu Y, Cao Y, Cummer SA, Xu Y, Chen H. Coherent perfect absorber and laser modes in purely imaginary metamaterials. Physical Review A. 2017 Oct 16;96(4).
• Bowers GS, Smith DM, Martinez-McKinney GF, Kamogawa M, Cummer SA, Dwyer JR, et al. Gamma Ray Signatures of Neutrons From a Terrestrial Gamma Ray Flash. Geophysical Research Letters. 2017 Oct 16;44(19):10–070.
• Liu N, Dwyer JR, Cummer SA. Elves Accompanying Terrestrial Gamma Ray Flashes. Journal of Geophysical Research: Space Physics. 2017 Oct 1;122(10):10–576.
• Lu G, Cummer SA, Chen AB, Lyu F, Li D, Liu F, et al. Analysis of lightning strokes associated with sprites observed by ISUAL in the vicinity of North America. Terrestrial, Atmospheric and Oceanic Sciences. 2017 Aug 1;28(4):583–95.
• Li Y, Shen C, Xie Y, Li J, Wang W, Cummer SA, et al. Tunable Asymmetric Transmission via Lossy Acoustic Metasurfaces. Physical review letters. 2017 Jul;119(3):035501.
• Xie Y, Ye S, Reyes C, Sithikong P, Popa BI, Wiley BJ, et al. Microwave metamaterials made by fused deposition 3D printing of a highly conductive copper-based filament. Applied Physics Letters. 2017 May 1;110(18).
• Carvalho FL, Uman MA, Jordan DM, Hill JD, Cummer SA, Kotovsky DA, et al. Triggered lightning sky waves, return stroke modeling, and ionosphere effective height. Journal of Geophysical Research. 2017 Jan 1;122(6):3507–27.
• Wang W, Xie Y, Popa BI, Cummer SA. Subwavelength diffractive acoustics and wavefront manipulation with a reflective acoustic metasurface. Journal of Applied Physics. 2016 Nov 21;120(19).
• Xie Y, Shen C, Wang W, Li J, Suo D, Popa B-I, et al. Acoustic Holographic Rendering with Two-dimensional Metamaterial-based Passive Phased Array. Scientific reports. 2016 Oct;6:35437.
• Li J, Wang W, Xie Y, Popa BI, Cummer SA. A sound absorbing metasurface with coupled resonators. Applied Physics Letters. 2016 Aug 29;109(9).
• Lyu F, Cummer SA, Briggs M, Marisaldi M, Blakeslee RJ, Bruning E, et al. Ground detection of terrestrial gamma ray flashes from distant radio signals. Geophysical Research Letters. 2016 Aug 28;43(16):8728–34.
• Barrett JP, Katko AR, Cummer SA. Transistor-based metamaterials with dynamically tunable nonlinear susceptibility. Applied Physics Letters. 2016 Aug 8;109(6).
• Lu G, Fan Y, Zhang H, Jiang R, Liu M, Qie X, et al. Reconstructing initial continuous current waveform in rocket-triggered lightning with close magnetic measurement. In: 2016 Asia-Pacific International Symposium on Electromagnetic Compatibility, APEMC 2016. 2016. p. 15–8.
• Mezentsev A, Østgaard N, Gjesteland T, Albrechtsen K, Lehtinen N, Marisaldi M, et al. Radio emissions from double RHESSI TGFs. Journal of geophysical research Atmospheres : JGR. 2016 Jul;121(13):8006–22.
• Popa B-I, Wang W, Konneker A, Cummer SA, Rohde CA, Martin TP, et al. Anisotropic acoustic metafluid for underwater operation. The Journal of the Acoustical Society of America. 2016 Jun;139(6):3325.
• Shen C, Xie Y, Li J, Cummer SA, Jing Y. Asymmetric acoustic transmission through near-zero-index and gradient-index metasurfaces. Applied Physics Letters. 2016 May 30;108(22).
• Popa BI, Cummer SA. Preserving omnidirectionality in optimized asymmetric transformation optics designs. Journal of Optics (United Kingdom). 2016 Apr 1;18(4).
• Liu N, Boggs LD, Cummer SA. Observation-constrained modeling of the ionospheric impact of negative sprites. Geophysical Research Letters. 2016 Mar 28;43(6):2365–73.
• Cummer SA, Christensen J, Alù A. Controlling sound with acoustic metamaterials. Nature Reviews Materials. 2016 Feb 16;1.
• Kolmašová I, Santolík O, Farges T, Cummer SA, Lán R, Uhlíř L. Subionospheric propagation and peak currents of preliminary breakdown pulses before negative cloud-to-ground lightning discharges. Geophysical Research Letters. 2016 Feb 16;43(3):1382–91.
• Boggs LD, Liu N, Splitt M, Lazarus S, Glenn C, Rassoul H, et al. An analysis of five negative sprite-parent discharges and their associated thunderstorm charge structures. Journal of Geophysical Research. 2016 Jan 27;121(2):759–84.
• Xu L, Chen H, Tyc T, Xie Y, Cummer SA. Perfect conformal invisible device with feasible refractive indexes. Physical Review B. 2016 Jan 6;93(4).
• Hare BM, Uman MA, Dwyer JR, Jordan DM, Biggerstaff MI, Caicedo JA, et al. Ground-level observation of a terrestrial gamma ray flash initiated by a triggered lightning. Journal of Geophysical Research. 2016 Jan 1;121(11):6511–33.
• Lu G, Cummer SA, Tian Y, Zhang H, Lyu F, Wang T, et al. Sprite produced by consecutive impulse charge transfers following a negative stroke: Observation and simulation. Journal of Geophysical Research. 2016 Jan 1;121(8):4082–92.
• Lyu F, Cummer SA, Lu G, Zhou X, Weinert J. Imaging lightning intracloud initial stepped leaders by low-frequency interferometric lightning mapping array. Geophysical Research Letters. 2016 Jan 1;43(10):5516–23.
• Lang TJ, Lyons WA, Cummer SA, Fuchs BR, Dolan B, Rutledge SA, et al. Observations of two sprite-producing storms in Colorado. Journal of Geophysical Research. 2016 Jan 1;121(16):9675–95.
• Barrett JP, Katko AR, Cummer SA. Bandwidth tuning in transistor embedded metamaterials using variable resistance. Progress in Electromagnetics Research. 2016 Jan 1;157:49–61.
• McTague LE, Cummer SA, Briggs MS, Connaughton V, Stanbro M, Fitzpatrick G. A lightning-based search for nearby observationally dim terrestrial gamma ray flashes. Journal of Geophysical Research. 2015 Dec 16;120(23):12–017.
• Somu VB, Rakov VA, Haddad MA, Cummer SA. A study of changes in apparent ionospheric reflection height within individual lightning flashes. Journal of Atmospheric and Solar-Terrestrial Physics. 2015 Dec 1;136:66–79.
• Barrett JP, Cummer SA. Design and full characterization of planar active magnetic RF metamaterials. IEEE Antennas and Wireless Propagation Letters. 2015 Dec 1;14:943–6.
• Shen C, Xie Y, Sui N, Wang W, Cummer SA, Jing Y. Broadband Acoustic Hyperbolic Metamaterial. Physical review letters. 2015 Dec;115(25):254301.
• Kolmasova I, Santolik O, Farges T, Cummer S, Lan R, Uhlir L. Propagation of preliminary breakdown pulses preceding cloud-to-ground lightning discharges. In: 2015 1st URSI Atlantic Radio Science Conference, URSI AT-RASC 2015. 2015.
• Cummer SA, Lyu F, Briggs MS, Fitzpatrick G, Roberts OJ, Dwyer JR. Lightning leader altitude progression in terrestrial gamma-ray flashes. Geophysical Research Letters. 2015 Sep 28;42(18):7792–8.
• Lyu F, Cummer SA, McTague L. Insights into high peak current in-cloud lightning events during thunderstorms. Geophysical Research Letters. 2015 Aug 28;42(16):6836–43.
• Xie Y, Tsai T-H, Konneker A, Popa B-I, Brady DJ, Cummer SA. Single-sensor multispeaker listening with acoustic metamaterials. Proceedings of the National Academy of Sciences of the United States of America. 2015 Aug;112(34):10595–8.
• Popa BI, Shinde D, Konneker A, Cummer SA. Active acoustic metamaterials reconfigurable in real time. Physical Review B - Condensed Matter and Materials Physics. 2015 Jun 30;91(22).
• Popa B-I, Cummer SA. Water-based metamaterials: Negative refraction of sound. Nature materials. 2015 Apr;14(4):363–4.
• Liu N, Spiva N, Dwyer JR, Rassoul HK, Free D, Cummer SA. Upward electrical discharges observed above Tropical Depression Dorian. Nature communications. 2015 Jan;6:5995.
• Cummer SA. Active and applied functional rf metamaterials. Springer Series in Materials Science. 2015 Jan 1;200:21–33.
• Lang TJ, Cummer SA, Petersen D, Flores-Rivera L, Lyons WA, MacGorman D, et al. Large charge moment change lightning on 31 May to 1 June 2013, including the El Reno tornadic storm. Journal of Geophysical Research. 2015 Jan 1;120(8):3354–69.
• Cummer SA, Briggs MS, Dwyer JR, Xiong S, Connaughton V, Fishman GJ, et al. The source altitude, electric current, and intrinsic brightness of terrestrial gamma ray flashes. Geophysical Research Letters. 2014 Dec 16;41(23):8586–93.
• Lu G, Cummer SA. Implications of lightning emissions for terrestrial gamma-ray flashes and associated lightning discharges. In: 2014 International Conference on Lightning Protection, ICLP 2014. 2014. p. 1496–502.
• Lyu F, Cummer SA, Solanki R, Weinert J, McTague L, Katko A, et al. A low-frequency near-field interferometric-TOA 3-D Lightning Mapping Array. Geophysical Research Letters. 2014 Nov 28;41(22):7777–84.
• Popa BI, Cummer SA. Unified approach to design linear and nonlinear acoustic metamaterials. In: 2014 8th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics, METAMATERIALS 2014. 2014. p. 241–3.
• Xie Y, Wang W, Chen H, Konneker A, Popa B-I, Cummer SA. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface. Nature communications. 2014 Nov;5:5553.
• Lu G, Cummer SA. Negative sprites produced by consecutive impulse charge transfers in negative strokes. In: 2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014. 2014.
• Cummer SA, Briggs MS, Connaughton V, Xiong S, Fishman GJ, Dwyer JR. Charge motion and altitude of terrestrial gamma-ray flashes. In: 2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014. 2014.
• Qin J, Celestin S, Pasko VP, Cummer SA, McHarg MG, Stenbaek-Nielsen HC. Mechanisms of sprite initiation, morphology, and lightning polarity asymmetry. In: 2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014. 2014.
• Katko AR, Cummer SA. Transistor-embedded acousto-optic and nonlinear metamaterials. In: 2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014. 2014.
• Barrett JP, Cummer SA. Design and realization of transistor-embedded active RF metamaterials. In: 2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014. 2014.
• Weinert JL, Cummer SA. Measurement of sensitive current and charge motion using coherent averaging of remote low frequency magnetic field observations. In: 2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014. 2014.
• Barrett JP, Cummer SA. Roadmap to electrically self-tuning metamaterials: Design and experimental validation. In: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. 2014. p. 341–2.
• Wang W, Xie Y, Konneker A, Popa BI, Cummer SA. Design and demonstration of broadband thin planar diffractive acoustic lenses. Applied Physics Letters. 2014 Sep 8;105(10).
• Cummer SA. Design for simplified materials in transformation electromagnetics. In: Transformation Electromagnetics and Metamaterials: Fundamental Principles and Applications. 2014. p. 117–37.
• Liu L, Katko AR, Li D, Cummer SA. Broadband electromagnetic metamaterials with reconfigurable fluid channels. Physical Review B - Condensed Matter and Materials Physics. 2014 Jun 25;89(24).
• Katko AR, Barrett JP, Cummer SA. Time-varying transistor-based metamaterial for tunability, mixing, and efficient phase conjugation. Journal of Applied Physics. 2014 Apr 14;115(14).
• Zigoneanu L, Popa B-I, Cummer SA. Three-dimensional broadband omnidirectional acoustic ground cloak. Nature materials. 2014 Apr;13(4):352–5.
• Xie Y, Tsai TH, Brady DJ, Cummer SA. Compressive acoustic imaging with metamaterials. The Journal of the Acoustical Society of America. 2014 Apr;135(4):2394.
• Xie Y, Konneker A, Popa BI, Cummer SA. Tapered labyrinthine acoustic metamaterials for coherent controlling of acoustic wave. The Journal of the Acoustical Society of America. 2014 Apr;135(4):2222.
• Popa B-I, Cummer SA. Non-reciprocal and highly nonlinear active acoustic metamaterials. Nature communications. 2014 Feb;5:3398.
• Cummins KL, Quick MG, Rison W, Krehbiel P, Thomas R, Rodeheffer D, et al. Overview of the Kansas Windfarm 2013 field program. In: International Conference on Atmospheric Electricity, ICAE 2014. 2014.
• Cummer SA. Applied physics. Selecting the direction of sound transmission. Science (New York, NY). 2014 Jan;343(6170):495–6.
• Lang TJ, Cummer S, Petersen D, Flores-Rivera L, Lyons W, MacGorman D, et al. Large charge moment change lightning in an Oklahoma mesoscale convective system. In: International Conference on Atmospheric Electricity, ICAE 2014. 2014.
• Lang TJ, Cummer S, Petersen D, Flores-Rivera L, Lyons W, MacGorman D, et al. Large charge moment change lightning in an Oklahoma mesoscale convective system. In: International Conference on Atmospheric Electricity, ICAE 2014. 2014.
• Cummins KL, Quick MG, Rison W, Krehbiel P, Thomas R, Rodeheffer D, et al. Overview of the Kansas Windfarm 2013 field program. In: International Conference on Atmospheric Electricity, ICAE 2014. 2014.
• Yaniv R, Yair Y, Price C, Bór J, Sato M, Hobara Y, et al. Ground-based observations of the relations between lightning charge-moment-change and the physical and optical properties of column sprites. Journal of Atmospheric and Solar-Terrestrial Physics. 2014 Jan 1;107:60–7.
• Beavis NK, Lang TJ, Rutledge SA, Lyons WA, Cummer SA. Regional, seasonal, and diurnal variations of cloud-to-ground lightning with large impulse charge moment changes. Monthly Weather Review. 2014 Jan 1;142(10):3666–82.
• Katko AR, Cummer SA. Functional metamaterials for wireless phase conjugation. CLEO: QELS_Fundamental Science, CLEO:QELS FS 2013. 2013 Nov 21;
• Xie Y, Konneker A, Popa BI, Cummer SA. Tapered labyrinthine acoustic metamaterials for broadband impedance matching. Applied Physics Letters. 2013 Nov 11;103(20).
• Marshall T, Stolzenburg M, Karunarathne S, Cummer S, Lu G, Betz HD, et al. Initial breakdown pulses in intracloud lightning flashes and their relation to terrestrial gamma ray flashes. Journal of Geophysical Research Atmospheres. 2013 Oct 16;118(19):10–925.
• Qin J, Celestin S, Pasko VP, Cummer SA, McHarg MG, Stenbaek-Nielsen HC. Mechanism of column and carrot sprites derived from optical and radio observations. Geophysical Research Letters. 2013 Sep 16;40(17):4777–82.
• Lang TJ, Cummer SA, Rutledge SA, Lyons WA. The meteorology of negative cloud-to-ground lightning strokes with large charge moment changes: Implications for negative sprites. Journal of Geophysical Research Atmospheres. 2013 Jul 27;118(14):7886–96.
• Popa BI, Zigoneanu L, Cummer SA. Tunable active acoustic metamaterials. Physical Review B - Condensed Matter and Materials Physics. 2013 Jul 16;88(2).
• Lu G, Cummer SA, Li J, Zigoneanu L, Lyons WA, Stanley MA, et al. Coordinated observations of sprites and in-cloud lightning flash structure. Journal of Geophysical Research Atmospheres. 2013 Jun 27;118(12):6607–32.
• Cummer SA, Lyons WA, Stanley MA. Three years of lightning impulse charge moment change measurements in the United States. Journal of Geophysical Research Atmospheres. 2013 Jun 16;118(11):5176–89.
• Dwyer JR, Cummer SA. Radio emissions from terrestrial gamma-ray flashes. Journal of Geophysical Research: Space Physics. 2013 Jun 1;118(6):3769–90.
• Østgaard N, Gjesteland T, Carlson BE, Collier AB, Cummer SA, Lu G, et al. Simultaneous observations of optical lightning and terrestrial gamma ray flash from space. Geophysical Research Letters. 2013 May 28;40(10):2423–6.
• Meyer TC, Lang TJ, Rutledge SA, Lyons WA, Cummer SA, Lu G, et al. Radar and lightning analyses of gigantic jet-producing storms. Journal of Geophysical Research Atmospheres. 2013 Apr 16;118(7):2872–88.
• Xie Y, Popa B-I, Zigoneanu L, Cummer SA. Measurement of a broadband negative index with space-coiling acoustic metamaterials. Physical review letters. 2013 Apr;110(17):175501.
• Hawkes AM, Katko AR, Cummer SA. A microwave metamaterial with integrated power harvesting functionality. APPLIED PHYSICS LETTERS. 2013;103(16).
• Katko AR, Cummer SA. Functional metamaterials for wireless phase conjugation. 2013 Conference on Lasers and Electro-Optics, CLEO 2013. 2013 Jan 1;
• Barrett JP, Cummer SA. Active nonlinear metamaterials loaded with negative differential resistance elements and circuits. In: Proceedings of SPIE - The International Society for Optical Engineering. 2012.
• Katko AR, Hawkes AM, Cummer SA. Nonlinear and active RF metamaterial applications using embedded devices. In: Proceedings of SPIE - The International Society for Optical Engineering. 2012.
• Zigoneanu L, Popa BI, Cummer SA. Sound manipulation with acoustic metamaterials. 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012. 2012 Dec 1;2:1555–62.
• Dwyer JR, Smith DM, Cummer SA. High-energy atmospheric physics: Terrestrial gamma-ray flashes and related phenomena. Space Science Reviews. 2012 Nov 1;173(1–4):133–96.
• Li D, Zigoneanu L, Popa B-I, Cummer SA. Design of an acoustic metamaterial lens using genetic algorithms. The Journal of the Acoustical Society of America. 2012 Oct;132(4):2823–33.
• Popa BI, Cummer SA. Nonreciprocal active metamaterials. Physical Review B - Condensed Matter and Materials Physics. 2012 May 2;85(20).
• Haddad MA, Rakov VA, Cummer SA. New measurements of lightning electric fields in Florida: Waveform characteristics, interaction with the ionosphere, and peak current estimates. Journal of Geophysical Research Atmospheres. 2012 Jan 1;117(10).
• Li J, Cummer S. Relationship between sprite streamer behavior and lightning-driven electric fields. Journal of Geophysical Research: Space Physics. 2012 Jan 1;117(1).
• Li J, Cummer S, Lu G, Zigoneanu L. Charge moment change and lightning-driven electric fields associated with negative sprites and halos. Journal of Geophysical Research: Space Physics. 2012 Jan 1;117(9).
• Zigoneanu L, Popa BI, Cummer SA. Sound manipulation with acoustic metamaterials. In: American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD. 2012. p. 521–8.
• Thompson RT, Cummer SA. Transformation optics. 2012 Jan 1;171:195–295.
• Lu G, Cummer SA, Blakeslee RJ, Weiss S, Beasley WH. Lightning morphology and impulse charge moment change of high peak current negative strokes. Journal of Geophysical Research Atmospheres. 2012 Jan 1;117(4).
• Katko AR, Shvets G, Cummer SA. Phase conjugation metamaterials: Particle design and imaging experiments. Journal of Optics (United Kingdom). 2012 Jan 1;14(11).
• Hager WW, Sonnenfeld RG, Feng W, Kanmae T, Stenbaek-Nielsen HC, McHarg MG, et al. Charge rearrangement by sprites over a north Texas mesoscale convective system. Journal of Geophysical Research Atmospheres. 2012 Jan 1;117(22).
• Popa BI, Cummer SA. Complex coordinates in transformation optics. Physical Review A - Atomic, Molecular, and Optical Physics. 2011 Dec 16;84(6).
• Katko AR, Hawkes AM, Barrett JP, Cummer SA. RF limiter metamaterial using p-i-n diodes. IEEE Antennas and Wireless Propagation Letters. 2011 Dec 1;10:1571–4.
• Cummer SA, Lu G, Li J, Lyons WA, Beasley WH, MacGorman DR, et al. Observations of lightning flash development associated with gigantic jets. 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011. 2011 Nov 21;
• Cummer SA, Lu G, Li J, Blakeslee RJ, Smith DM, Dwyer JR, et al. Detailed observations of lightning flashes and processes associated with terrestrial gamma ray flashes. 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011. 2011 Nov 21;
• Cummer SA, Popa BI, Katko A. Powered and active RF metamaterials. 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011. 2011 Nov 21;
• Katko AR, Popa BI, Barrett JP, Hawkes AM, Cummer SA. Powered and nonlinear RF metamaterials. Proceedings of SPIE - The International Society for Optical Engineering. 2011 Oct 14;8093.
• Zigoneanu L, Popa BI, Cummer SA. Design and measurements of a broadband two-dimensional acoustic lens. Physical Review B - Condensed Matter and Materials Physics. 2011 Jul 26;84(2).
• Cummer SA, Lu G, Briggs MS, Connaughton V, Xiong S, Fishman GJ, et al. The lightning-TGF relationship on microsecond timescales. Geophysical Research Letters. 2011 Jul 1;38(14).
• Popa BI, Cummer SA. Homogeneous and compact acoustic ground cloaks. Physical Review B - Condensed Matter and Materials Physics. 2011 Jun 24;83(22).
• Lu G, Cummer SA, Lyons WA, Krehbiel PR, Li J, Rison W, et al. Lightning development associated with two negative gigantic jets. Geophysical Research Letters. 2011 Jun 1;38(12).
• Popa B-I, Zigoneanu L, Cummer SA. Experimental acoustic ground cloak in air. Physical review letters. 2011 Jun;106(25):253901.
• Smith DM, Dwyer JR, Hazelton BJ, Grefenstette BW, Martinez-Mckinney GFM, Zhang ZY, et al. The rarity of terrestrial gamma-ray flashes. Geophysical Research Letters. 2011 Apr 28;38(8).
• Zigoneanu L, Popa BI, Starr AF, Cummer SA. Design and measurements of a broadband two-dimensional acoustic metamaterial with anisotropic effective mass density. Journal of Applied Physics. 2011 Mar 1;109(5).
• Smith DM, Dwyer JR, Hazelton BJ, Grefenstette BW, Martinez-Mckinney GFM, Zhang ZY, et al. A terrestrial gamma ray flash observed from an aircraft. Journal of Geophysical Research Atmospheres. 2011 Jan 1;116(20).
• Thompson RT, Cummer SA, Frauendiener J. A completely covariant approach to transformation optics. Journal of Optics. 2011 Jan 1;13(2).
• Neubert T, Chanrion O, Arnone E, Zanotti F, Cummer S, Li J, et al. The properties of a gigantic jet reflected in a simultaneous sprite: Observations interpreted by a model. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(12).
• Zhai Y, Cummer SA, Green JL, Reinisch BW, Kaiser ML, Reiner MJ, et al. Magnetospheric radio tomographic imaging with IMAGE and Wind. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(12).
• Lang TJ, Li J, Lyons WA, Cummer SA, Rutledge SA, MacGorman DR. Transient luminous events above two mesoscale convective systems: Charge moment change analysis. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(10).
• Thompson RT, Cummer SA, Frauendiener J. Generalized transformation optics of linear materials. Journal of Optics. 2011 Jan 1;13(5).
• Cummer SA, Thompson RT. Frequency conversion by exploiting time in transformation optics. Journal of Optics. 2011 Jan 1;13(2).
• Han F, Cummer SA, Li J, Lu G. Daytime ionospheric D region sharpness derived from VLF radio atmospherics. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(5).
• Li J, Cummer S. Estimation of electric charge in sprites from optical and radio observations. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(1).
• Gamerota WR, Cummer SA, Li J, Stenbaek-Nielsen HC, Haaland RK, McHarg MG. Comparison of sprite initiation altitudes between observations and models. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(2).
• Lu G, Cummer SA, Li J, Han F, Smith DM, Grefenstette BW. Characteristics of broadband lightning emissions associated with terrestrial gamma ray flashes. Journal of Geophysical Research: Space Physics. 2011 Jan 1;116(3).
• Cummer SA. Transformation acoustics. 17th International Congress on Sound and Vibration 2010, ICSV 2010. 2010 Dec 1;1:197–202.
• Popa BI, Cummer SA. Design of layered transformation-optics devices of arbitrary shape. Physical Review A - Atomic, Molecular, and Optical Physics. 2010 Sep 30;82(3).
• Gu S, Barrett JP, Hand TH, Popa BI, Cummer SA. A broadband low-reflection metamaterial absorber. Journal of Applied Physics. 2010 Sep 15;108(6).
• Cohen MB, Inan US, Said RK, Briggs MS, Fishman GJ, Connaughton V, et al. A lightning discharge producing a beam of relativistic electrons into space. Geophysical Research Letters. 2010 Sep 1;37(18).
• Katko AR, Gu S, Barrett JP, Popa B-I, Shvets G, Cummer SA. Phase conjugation and negative refraction using nonlinear active metamaterials. Physical review letters. 2010 Sep;105(12):123905.
• Sajuyigbe S, Ross M, Geren P, Cummer SA, Tanielian MH, Smith DR. Wide angle impedance matching metamaterials for waveguide-fed phased-array antennas. IET Microwaves, Antennas and Propagation. 2010 Aug 1;4(8):1063–72.
• Chou JK, Kuo CL, Tsai LY, Chen AB, Su HT, Hsu RR, et al. Gigantic jets with negative and positive polarity streamers. Journal of Geophysical Research: Space Physics. 2010 Jul;115(A7).
• Lu G, Blakeslee RJ, Li J, Smith DM, Shao XM, McCaul EW, et al. Lightning mapping observation of a terrestrial gamma-ray flash. Geophysical Research Letters. 2010 Jun 1;37(11).
• Hand TH, Cummer SA. Reconfigurable reflectarray using addressable metamaterials. IEEE Antennas and Wireless Propagation Letters. 2010 Mar 19;9:70–4.
• Thomas JN, Solorzano NN, Cummer SA, Holzworth RH. Polarity and energetics of inner core lightning in three intense North Atlantic hurricanes. Journal of Geophysical Research: Space Physics. 2010 Mar;115(A3).
• Popa BL, Cummer SA. Theory and design of practical metamaterials for acoustic cloaking. ASME International Mechanical Engineering Congress and Exposition, Proceedings. 2010 Jan 1;15:113–4.
• Han F, Cummer SA. Midlatitude daytime D region ionosphere variations measured from radio atmospherics. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(10).
• Rodger CJ, Carson BR, Cummer SA, Gamble RJ, Clilverd MA, Green JC, et al. Contrasting the efficiency of radiation belt losses caused by ducted and nonducted whistler-mode waves from ground-based transmitters. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(12).
• Ybarra GA, Collins LM, Huettel LG, Coonley KD, Massoud HZ, Board JA, et al. Integrated sensing and information processing theme-based redesign of the undergraduate electrical and computer engineering curriculum at Duke University. Advances in Engineering Education. 2010;2(4).
• Williams ER, Lyons WA, Hobara Y, Mushtak VC, Asencio N, Boldi R, et al. Ground-based detection of sprites and their parent lightning flashes over Africa during the 2006 AMMA campaign. Quarterly Journal of the Royal Meteorological Society. 2010 Jan 1;136(SUPPL. 1):257–71.
• São Sabbas FT, Taylor MJ, Pautet PD, Bailey M, Cummer S, Azambuja RR, et al. Observations of prolific transient luminous event production above a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(11).
• Han F, Cummer SA. Midlatitude nighttime D region ionosphere variability on hourly to monthly time scales. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(9).
• Inan US, Cummer SA, Marshall RA. A survey of ELF and VLF research on lightning-ionosphere interactions and causative discharges. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(6).
• Lang TJ, Lyons WA, Rutledge SA, Meyer JD, MacGorman DR, Cummer SA. Transient luminous events above two mesoscale convective systems: Storm structure and evolution. Journal of Geophysical Research: Space Physics. 2010 Jan 1;115(5).
• Van Der Velde OA, Bór J, Li J, Cummer SA, Arnone E, Zanotti F, et al. Multi-instrumental observations of a positive gigantic jet produced by a winter thunderstorm in Europe. Journal of Geophysical Research Atmospheres. 2010 Jan 1;115(24).
• Lyons WA, Stanley MA, Meyer JD, Nelson TE, Rutledge SA, Lang TL, et al. The meteorological and electrical structure of TLE-producing convective storms. 2009 Dec 1;387–415.
• Hand TH, Cummer SA. Controllable magnetic metamaterial using digitally addressable split-ring resonators. IEEE Antennas and Wireless Propagation Letters. 2009 Dec 1;8:262–5.
• Popa BI, Cummer SA. Design and characterization of broadband acoustic composite metamaterials. Physical Review B - Condensed Matter and Materials Physics. 2009 Nov 25;80(17).
• Hand TH, Cummer SA. A dynamic frequency selective surface using addressable metamaterials. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2009 Nov 16;
• Sajuyigbe S, Cummer SA, Smith DR. Utilization of metamaterials for wide angle impedance matching (WAIM) in phased array antennas. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2009 Nov 16;
• Cummer SA, Kundtz N, Popa BI. Electromagnetic surface and line sources under coordinate transformations. Physical Review A - Atomic, Molecular, and Optical Physics. 2009 Sep 14;80(3).
• Cummer SA, Li J, Han F, Lu G, Jaugey N, Lyons WA, et al. Quantification of the troposphere-to-ionosphere charge transfer in a gigantic jet. Nature Geoscience. 2009 Sep 1;2(9):617–20.
• Adachi T, Cummer SA, Li J, Takahashi Y, Hsu RR, Su HT, et al. Estimating lightning current moment waveforms from satellite optical measurements. Geophysical Research Letters. 2009 Sep 1;36(18).
• Farrell WM, Plaut JJ, Cummer SA, Gurnett DA, Picardi G, Watters TR, et al. Is the Martian water table hidden from radar view? Geophysical Research Letters. 2009 Aug 16;36(15).
• Lu G, Cummer SA, Li J, Han F, Blakeslee RJ, Christian HJ. Charge transfer and in-cloud structure of large-charge-moment positive lightning strokes in a mesoscale convective system. Geophysical Research Letters. 2009 Aug 16;36(15).
• Yuan Y, Popa B-I, Cummer SA. Zero loss magnetic metamaterials using powered active unit cells. Optics express. 2009 Aug;17(18):16135–43.
• Popa BI, Allen J, Cummer SA. Conformal array design with transformation electromagnetics. Applied Physics Letters. 2009 Jun 29;94(24).
• Allen J, Kundtz N, Roberts DA, Cummer SA, Smith DR. Electromagnetic source transformations using superellipse equations. Applied Physics Letters. 2009 Jun 18;94(19).
• Li J, Cummer SA. Measurement of sprite streamer acceleration and deceleration. Geophysical Research Letters. 2009 May 28;36(10).
• Cummer SA, Liu R, Cui TJ. A rigorous and nonsingular two dimensional cloaking coordinate transformation. Journal of Applied Physics. 2009 Mar 24;105(5).
• Zhai Y, Cummer SA. Fast tomographic reconstruction strategy for diffuse optical tomography. Optics express. 2009 Mar;17(7):5285–97.
• Popa BI, Cummer SA. Cloaking with optimized homogeneous anisotropic layers. Physical Review A - Atomic, Molecular, and Optical Physics. 2009 Feb 2;79(2).
• Hazelton BJ, Grefenstette BW, Smith DM, Dwyer JR, Shao XM, Cummer SA, et al. Spectral dependence of terrestrial gamma-ray flashes on source distance. Geophysical Research Letters. 2009 Jan 16;36(1).
• Kuo CL, Chou JK, Tsai LY, Chen AB, Su HT, Hsu RR, et al. Discharge processes, electric field, and electron energy in ISUAL recorded gigantic jets. Journal of Geophysical Research: Space Physics. 2009 Jan 1;114(4).
• Cummer SA, Popa BI. Electromagnetic source transformations and applications. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2009 Jan 1;
• Hand TH, Gollub J, Sajuyigbe S, Smith DR, Cummer SA. Characterization of complementary electric field coupled resonant surfaces. Applied Physics Letters. 2008 Dec 8;93(21).
• Kundtz N, Roberts DA, Allen J, Cummer S, Smith DR. Optical source transformations. Optics express. 2008 Dec;16(26):21215–22.
• Cummer SA, Rahm M, Schurig D. Material parameters and vector scaling in transformation acoustics. New Journal of Physics. 2008 Nov 27;10.
• Yuan Y, Bingham C, Tyler T, Palit S, Hand TH, Padilla WJ, et al. A dual-resonant terahertz metamaterial based on single-particle electric-field-coupled resonators. Applied Physics Letters. 2008 Nov 21;93(19).
• Li J, Cummer SA, Lyons WA, Nelson TE. Coordinated analysis of delayed sprites with high-speed images and remote electromagnetic fields. Journal of Geophysical Research Atmospheres. 2008 Oct 27;113(20).
• Ross M, Cummer SA, Nielsen TK, Zhang Y. Simultaneous remote electric and magnetic field measurements of lightning continuing currents. Journal of Geophysical Research Atmospheres. 2008 Oct 27;113(20).
• Hand TH, Yu Y, Palit S, Bingham C, Rahm M, Smith DR, et al. Dual-band planar electric THz metamaterial with resonator yield analysis. 2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro-Optics, CLEO/QELS. 2008 Sep 15;
• Hand TH, Yuan Y, Palit S, Bingham C, Rahm M, Smith DR, et al. Dual-band planar electric THz metamaterial with resonator yield analysis. Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series. 2008 Sep 15;
• Erentok A, Ziolkowski RW, Nielsen JA, Greegor RB, Parazzoli CG, Tanielian MH, et al. Lumped element-based, highly sub-wavelength, negative index metamaterials at UHF frequencies. Journal of Applied Physics. 2008 Aug 25;104(3).
• Lyons WA, Cummer SA, Stanley MA, Huffines GR, Wiens KC, Nelson TE. Supercelles and sprites. Bulletin of the American Meteorological Society. 2008 Aug 1;89(8):1165–74.
• Taylor MJ, Bailey MA, Pautet PD, Cummer SA, Jaugey N, Thomas JN, et al. Rare measurements of a sprite with halo event driven by a negative lightning discharge over Argentina. Geophysical Research Letters. 2008 Jul 28;35(14).
• Yuan Y, Bingham C, Tyler T, Palit S, Hand TH, Padilla WJ, et al. Dual-band planar electric metamaterial in the terahertz regime. Optics express. 2008 Jun;16(13):9746–52.
• Popa B-I, Cummer SA. Compact dielectric particles as a building block for low-loss magnetic metamaterials. Physical review letters. 2008 May;100(20):207401.
• Farrell WM, Clifford SM, Milkovich SM, Plaut JJ, Leuschen CJ, Picardi G, et al. MARSIS subsurface radar investigations of the South Polar reentrant Chasma Australe. Journal of Geophysical Research: Planets. 2008 Apr 20;113(4).
• Hand TH, Cummer SA. Frequency tunable electromagnetic metamaterial using ferroelectric loaded split rings. Journal of Applied Physics. 2008 Apr 8;103(6).
• Rahm M, Schurig D, Roberts DA, Cummer SA, Smith DR, Pendry JB. Design of electromagnetic cloaks and concentrators using form-invariant coordinate transformations of Maxwell's equations. Photonics and Nanostructures - Fundamentals and Applications. 2008 Apr 1;6(1):87–95.
• Rahm M, Cummer SA, Schurig D, Pendry JB, Smith DR. Optical design of reflectionless complex media by finite embedded coordinate transformations. Physical review letters. 2008 Feb;100(6):063903.
• Liu R, Cheng Q, Hand T, Mock JJ, Cui TJ, Cummer SA, et al. Experimental demonstration of electromagnetic tunneling through an epsilon-near-zero metamaterial at microwave frequencies. Physical Review Letters. 2008 Jan;1(2).
• Hand TH, Yuan Y, Palit S, Bingham C, Rahm M, Smith DR, et al. Dual-band planar electric THz metamaterial with resonator yield analysis. Optics InfoBase Conference Papers. 2008 Jan 1;
• Cummer SA, Popa B-I, Schurig D, Smith DR, Pendry J, Rahm M, et al. Scattering theory derivation of a 3D acoustic cloaking shell. Physical review letters. 2008 Jan;100(2):024301.
• Hand TH, Yuan Y, Palit S, Bingham C, Rahm M, Smith DR, et al. Dual-band planar electric THz metamaterial with resonator yield analysis. Optics InfoBase Conference Papers. 2008 Jan 1;
• Cummer SA, Popa BI, Hand TH. Q-based design equations and loss limits for resonant metamaterials and experimental validation. IEEE Transactions on Antennas and Propagation. 2008 Jan 1;56(1):127–32.
• Cummer SA. Active and Tunable RF Metamaterials. In: Cui TJ, Smith DR, editors. PROCEEDINGS OF THE 2008 INTERNATIONAL WORKSHOP ON METAMATERIALS. IEEE; 2008. p. 9–9.
• Liu R, Cheng Q, Hand T, Mock JJ, Cui TJ, Cummer SA, et al. Experimental demonstration of electromagnetic tunneling through an epsilon-near-zero metamaterial at microwave frequencies. Physical review letters. 2008 Jan;100(2):023903.
• Cummer SA, Popa BI, Schurig D, Smith DR, Pendry J, Rahm M, et al. Scattering theory derivation of a 3D acoustic cloaking shell. Physical Review Letters. 2008 Jan;1(2).
• Popa BI, Cummer SA. Design and experimental demonstration of active RF metamaterials. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2007 Dec 1;2546–9.
• Parazzoli CG, Greegor RB, Tanielian MH, Smith DR, Cummer S, Schurig D, et al. Applications of metamaterials in the GHz frequency domain. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2007 Dec 1;1152–5.
• Hand T, Cummer S. Characterization of tunable metamaterial elements using MEMS switches. IEEE Antennas and Wireless Propagation Letters. 2007 Dec 1;6:401–4.
• Erentok A, Ziolkowski RW, Nielsen JA, Greegor RB, Parazzoli CG, Tanielian MH, et al. Low frequency lumped element-based negative index metamaterial. Applied Physics Letters. 2007 Nov 7;91(18).
• Kuo CL, Chen AB, Lee YJ, Tsai LY, Chou RK, Hsu RR, et al. Modeling elves observed by FORMOSAT-2 satellite. Journal of Geophysical Research: Space Physics. 2007 Nov 1;112(11).
• Gollub J, Hand T, Sajuyigbe S, Mendonca S, Cummer S, Smith DR. Characterizing the effects of disorder in metamaterial structures. Applied Physics Letters. 2007 Oct 31;91(16).
• van der Velde OA, Lyons WA, Nelson TE, Cummer SA, Li J, Bunnell J. Analysis of the first gigantic jet recorded over continental North America. Journal of Geophysical Research Atmospheres. 2007 Oct 27;112(20).
• Popa BI, Cummer SA. An architecture for active metamaterial particles and experimental validation at RF. Microwave and Optical Technology Letters. 2007 Oct 1;49(10):2574–7.
• Frey HU, Mende SB, Cummer SA, Li J, Adachi T, Fukunishi H, et al. Halos generated by negative cloud-to-ground lightning. Geophysical Research Letters. 2007 Sep 28;34(18).
• Hu W, Cummer SA, Lyons WA. Testing sprite initiation theory using lightning measurements and modeled electromagnetic fields. Journal of Geophysical Research Atmospheres. 2007 Jul 16;112(13).
• Cheng Z, Cummer SA, Su HT, Hsu RR. Broadband very low frequency measurement of D region ionospheric perturbations caused by lightning electromagnetic pulses. Journal of Geophysical Research: Space Physics. 2007 Jun 1;112(6).
• Hand T, Cummer SA, Engheta N. The measured electric field spatial distribution within a metamaterial subwavelength cavity resonator. IEEE Transactions on Antennas and Propagation. 2007 Jun 1;55(6 II):1781–8.
• Thomas JN, Taylor MJ, Pautet D, Bailey M, Solorzano NN, Holzworth RH, et al. A very active sprite-producing storm observed over Argentina. Eos. 2007 Mar 6;88(10).
• Cummer SA, Schurig D. One path to acoustic cloaking. New Journal of Physics. 2007 Mar 2;9.
• Popa B-I, Cummer SA. Design and experimental demonstration of active RE metamaterials. In: 2007 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-12. IEEE; 2007. p. 2339–42.
• Brown A, Ybarra G, Massoud H, Board J, Holmes J, Coonley K, et al. Redesign of the core curriculum at Duke University. In: ASEE Annual Conference and Exposition, Conference Proceedings. 2006.
• Farrell WM, Marshall JR, Cummer SA, Delory GT, Desch MD. A model of the ULF magnetic and electric field generated from a dust devil. Journal of Geophysical Research: Planets. 2006 Nov 20;111(11).
• Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, et al. Metamaterial electromagnetic cloak at microwave frequencies. Science (New York, NY). 2006 Nov;314(5801):977–80.
• Cummer SA, Frey HU, Mende SB, Hsu RR, Su HT, Chen AB, et al. Simultaneous radio and satellite optical measurements of high-altitude sprite current and lightning continuing current. Journal of Geophysical Research: Space Physics. 2006 Oct 1;111(10).
• Popa B-I, Cummer SA. Derivation of effective parameters of magnetic metamaterials composed of passive resonant LC inclusions. 2006 Sep 28;
• Cummer SA, Popa B-I, Schurig D, Smith DR, Pendry J. Full-wave simulations of electromagnetic cloaking structures. Physical review E, Statistical, nonlinear, and soft matter physics. 2006 Sep;74(3 Pt 2):036621.
• Xu Y, Cummer SA, Farrell WM. Application of an orbital radar sounder model to detecting Martian polar subsurface features. Journal of Geophysical Research: Planets. 2006 Jun 20;111(6).
• Zhai Y, Cummer SA, Farrell WM. Quasi-electrostatic field analysis and simulation of Martian and terrestrial dust devils. Journal of Geophysical Research: Planets. 2006 Jun 20;111(6).
• Atreya SK, Wong A-S, Renno NO, Farrell WM, Delory GT, Sentman DD, et al. Oxidant enhancement in martian dust devils and storms: implications for life and habitability. Astrobiology. 2006 Jun;6(3):439–50.
• Delory GT, Farrell WM, Atreya SK, Renno NO, Wong A-S, Cummer SA, et al. Oxidant enhancement in martian dust devils and storms: storm electric fields and electron dissociative attachment. Astrobiology. 2006 Jun;6(3):451–62.
• Cheng Z, Cummer SA, Baker DN, Kanekal SG. Nighttime D region electron density profiles and variabilities inferred from broadband measurements using VLF radio emissions from lightning. Journal of Geophysical Research: Space Physics. 2006 May 1;111(5).
• Hu W, Cummer SA. An FDTD model for low and high altitude lightning-generated EM fields. IEEE Transactions on Antennas and Propagation. 2006 May 1;54(5):1513–22.
• Zhai Y, Cummer SA. An orthogonal projection and regularization technique for magnetospheric radio tomography. Journal of Geophysical Research: Space Physics. 2006 Mar 1;111(3).
• Farrell WM, Renno N, Delory GT, Cummer SA, Marshall JR. Integration of electrostatic and fluid dynamics within a dust devil. Journal of Geophysical Research: Planets. 2006 Jan 20;111(1).
• Brown A, Ybarra G, Massoud H, Board J, Holmes J, Coonley K, et al. Redesign of the core curriculum at Duke University. In: ASEE Annual Conference and Exposition, Conference Proceedings. 2006.
• Cummer SA. Measurements of lightning parameters from remote electromagnetic fields. In: Fullekrug M, Mareev EA, Rycroft MJ, editors. SPRITES, ELVES AND INTENSE LIGHTNING DISCHARGES. SPRINGER; 2006. p. 191-+.
• Cummer SA, Jaugey N, Li J, Lyons WA, Nelson TE, Gerken EA. Submillisecond imaging of sprite development and structure. Geophysical Research Letters. 2006;33(4):04104.
• Popa B-I, Cummer SA. Direct measurement of evanescent wave enhancement inside passive metamaterials. Physical review E, Statistical, nonlinear, and soft matter physics. 2006 Jan;73(1 Pt 2):016617.
• Lyons WA, Cummer SA. Lightning characteristics of the aurora, NE record hailstone-producing supercell of 22-23 June 2003 during BAMEX. 85th AMS Annual Meeting, American Meteorological Society - Combined Preprints. 2005 Dec 1;5685–90.
• Popa BI, Cummer SA. Determining the effective electromagnetic properties of negative-refractive-index metamaterials from internal fields. Physical Review B - Condensed Matter and Materials Physics. 2005 Oct 15;72(16).
• Frey HU, Mende SB, Cummer SA, Chen AB, Hsu RR, Su HT, et al. Beta-type stepped leader of elve-producing lightning. Geophysical Research Letters. 2005 Jul 16;32(13):1–4.
• Zhai Y, Cummer SA. A flexible and robust direct reconstruction method for magnetospheric radio tomography. Radio Science. 2005 May 1;40(3).
• Cheng Z, Cummer SA. Broadband VLF measurements of lightning-induced ionospheric perturbations. Geophysical Research Letters. 2005 Apr 28;32(8):1–4.
• Cummer SA, Zhai Y, Hu W, Smith DM, Lopez LI, Stanley MA. Measurements and implications of the relationship between lightning and terrestrial gamma ray flashes. Geophysical Research Letters. 2005 Apr 28;32(8):1–5.
• Collins LM, Huettel LG, Brown AS, Ybarra GA, Holmes JS, Board JA, et al. Theme-based redesign of the duke university ECE curriculum: The first steps. In: ASEE Annual Conference and Exposition, Conference Proceedings. 2005. p. 14313–26.
• Cummer SA, Lyons WA. Implications of lightning charge moment changes for sprite initiation. Journal of Geophysical Research: Space Physics. 2005 Jan 1;110(A4).
• Cummer SA. Perfectly matched layer behavior in negative refractive index materials. IEEE Antennas and Wireless Propagation Letters. 2004 Dec 1;3(1):172–5.
• Hu W, Cummer SA. The nearly perfectly matched layer is a perfectly matched layer. IEEE Antennas and Wireless Propagation Letters. 2004 Dec 1;3(1):137–40.
• Antunovic M, Cummer SA. Event driven adaptive filtering. Proceedings of the Mediterranean Electrotechnical Conference - MELECON. 2004 Nov 29;1:251–4.
• Cummer SA, Popa BL. Wave fields measured inside a negative refractive index metamaterial. Applied Physics Letters. 2004 Nov 15;85(20):4564–6.
• Farrell WM, Smith PH, Delory GT, Hillard GB, Marshall JR, Catling D, et al. Electric and magnetic signatures of dust devils from the 2000-2001 MATADOR desert tests. Journal of Geophysical Research: Planets. 2004 Mar 25;109(3).
• Cummer SA, Lyons WA. Lightning charge moment changes in U.S. High Plains thunderstorms. Geophysical Research Letters. 2004 Mar 16;31(5).
• Antunovic M, Cummer SA. Adaptive filter for event-based signal extraction. Automatika (Croatia). 2004;45(3–4):129–35.
• Farrell WM, Delory GT, Cummer SA, Marshall JR. A simple electrodynamic model of a dust devil. Geophysical Research Letters. 2003 Oct 15;30(20).
• Lyons WA, Nelson TE, Williams ER, Cummer SA, Stanley MA. Characteristics of sprite-producing positive cloud-to-ground lightning during the 19 July 2000 STEPS mesoscale convective systems. Monthly Weather Review. 2003 Oct 1;131(10):2417–27.
• Hu W, Cummer SA. A new FDTD model for lightning generated EM wave simulation. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2003 Sep 1;3:1061–4.
• Xu Y, Cummer SA. Applying the nonuniform FFT to the parabolic equation split-step algorithm for high frequency propagation modeling. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 2003 Sep 1;2:598–601.
• Cummer SA. Dynamics of causal beam refraction in negative refractive index materials. Applied Physics Letters. 2003 Mar 31;82(13):2008–10.
• Cummer SA. Simulated causal subwavelength focusing by a negative refractive index slab. Applied Physics Letters. 2003 Mar 10;82(10):1503–5.
• Cummer SA. A simple, nearly perfectly matched layer for general electromagnetic media. IEEE Microwave and Wireless Components Letters. 2003 Mar 1;13(3):128–30.
• Barros Ana P, Lang Timothy J. Monitoring the monsoon in the Himalayas: Observations in Central Nepal, June 2001. Monthly Weather Review. 2003;131(7):1408–27.
• Cummer SA, Green JL, Reinisch BW, Fung SF, Kaiser ML, Pickett JS, et al. Advances in magnetospheric radio wave analysis and tomography. Advances in Space Research. 2003 Jan 1;32(3):329–36.
• Cummer SA. Current moment in sprite-producing lightning. Journal of Atmospheric and Solar-Terrestrial Physics. 2003 Jan 1;65(5):499–508.
• Hu W, Cummer SA, Lyons WA, Nelson TE. Lightning charge moment changes for the initiation of sprites. Geophysical Research Letters. 2002 Apr 15;29(8).
• Hu W, Cummer SA, Lyons WA, Nelson TE. Lightning charge moment changes for the initiation of sprites. Geophysical Research Letters. 2002 Apr 15;29(8):120-1-120–4.
• Østgaard N, Stadsnes J, Bjordal J, Germany GA, Vondrak RR, Parks GK, et al. Auroral electron distributions derived from combined UV and X-ray emissions. Journal of Geophysical Research: Space Physics. 2001 Nov 1;106(A11):26081–9.
• Cummer SA, Reiner MJ, Reinisch BW, Kaiser ML, Green JL, Benson RF, et al. A test magnetospheric radio tomographic imaging with IMAGE and WIND. Geophysical Research Letters. 2001 Mar 15;28(6):1131–4.
• Cummer SA, Füllekrug M. Unusually intense continuing current in lightning produces delayed mesospheric breakdown. Geophysical Research Letters. 2001 Feb 1;28(3):495–8.
• Cummer SA, Inan US. Ionospheric E region remote sensing with ELF radio atmospherics. Radio Science. 2000 Nov 1;35(6):1437–44.
• Østgaard N, Stadsnes J, Bjordal J, Vondrak RR, Cummer SA, Chenette DL, et al. Cause of the localized maximum of X-ray emission in the morning sector: A comparison with electron measurements. Journal of Geophysical Research: Space Physics. 2000 Sep 1;105(A9):20869–83.
• Cummer SA. Modeling electromagnetic propagation in the Earth-ionosphere waveguide. IEEE Transactions on Antennas and Propagation. 2000 Sep 1;48(9):1420–9.
• Stanley M, Brook M, Krehbiel P, Cummer SA. Detection of daytime sprites via a unique sprite ELF signature. Geophysical Research Letters. 2000 Mar 15;27(6):871–4.
• Cummer SA, Vondrak RR, Ostgaard N, Stadsnes J, Bjordal J, Chenette DL, et al. Global multispectral auroral imaging of an isolated substorm. Geophysical Research Letters. 2000 Mar 1;27(5):637–40.
• Cummer SA, Vondrak RR, Østgaard N, Stadsnes J, Bjordal J, Chenette DL, et al. Global multispectral auroral imaging of an isolated substorm. Geophysical Research Letters. 2000 Mar 1;27(5):637–40.
• Cummer SA, Inan US. Modeling ELF radio atmospheric propagation and extracting lightning currents from ELF observations. Radio Science. 2000 Mar 1;35(2):385–94.
• Cummer SA, Vondrak RR, Pfaff RF, Gierloev JW, Carlson CW, Ergun RE, et al. Auroral surge currents and electrodynamics with FAST and VIS. In 2000. p. 191–7.
• Gjerloev JW, Friis-Christensen E, Hoffman RA, Cummer SA. The Harang discontinuity in auroral substorms. In 2000. p. 209–16.
• Østgaard N, Stadsnes J, Bjordal J, Vondrak RR, Cummer SA, Chenette DL, et al. Global X-ray emission during an isolated substorm - A case study. Journal of Atmospheric and Solar-Terrestrial Physics. 2000 Jan 1;62(10):889–900.
• Barrington-Leigh CP, Inan US, Stanley M, Cummer SA. Sprites triggered by negative lightning discharges. Geophysical Research Letters. 1999 Dec 15;26(24):3605–8.
• Cummer SA, Stanley M. Submillisecond resolution lightning currents and sprite development: Observations and implications. Geophysical Research Letters. 1999 Oct 15;26(20):3205–8.
• Cummer SA, Farrell WM. Radio atmospheric propagation on Mars and potential remote sensing applications. Journal of Geophysical Research: Planets. 1999 Jun 25;104(E6):14149–57.
• Østgaard N, Stadsnes J, Bjordal J, Vondrak RR, Cummer SA, Chenette DL, et al. Global-scale electron precipitation features seen in UV and X rays during substorms. Journal of Geophysical Research: Space Physics. 1999 May 1;104(A5):10191–204.
• Farrell WM, Kaiser ML, Desch MD, Houser JG, Cummer SA, Wilt DM, et al. Detecting electrical activity from Martian dust storms. Journal of Geophysical Research: Planets. 1999 Feb 25;104(E2):3795–801.
• Cummer SA, Inan US, Bell TF, Barrington-Leigh CP. ELF radiation produced by electrical currents in sprites. Geophysical Research Letters. 1998 Apr 15;25(8):1281–4.
• Cummer SA, Inan US. Erratum: Measurement of charge transfer in spriteproducing lightning using ELF radio atmospherics (Geophysical Research Letters (1998) 24:14 (1731-1734)). Geophysical Research Letters. 1998 Mar 15;25(6):901.
• Foster JC, Cummer S, Inan US. Midlatitude particle and electric field effects at the onset of the November 1993 geomagnetic storm. Journal of Geophysical Research: Space Physics. 1998 Jan 1;103(A11):26359–66.
• Cummer SA, Inan US, Bell TF. Ionospheric D region remote sensing using VLF radio atmospherics. Radio Science. 1998 Jan 1;33(6):1781–92.
• Cummer SA. An Analysis of New and Existing FDTD methods for isotropie cold plasma and a method for improving their accuracy. IEEE Transactions on Antennas and Propagation. 1997 Dec 1;45(3):392–400.
• Cummer SA, Inan US. Measurement of charge transfer in sprite-producing lightning using ELF radio atmospherics. Geophysical Research Letters. 1997 Jan 1;24(14):1731–4.
• Cummer SA. VLF remote sensing of high-energy auroral particle precipitation. Journal of Geophysical Research: Space Physics. 1997 Jan 1;102(A4):7477–84.
• Kelley MC, Baker SD, Holzworth RH, Argo P, Cummer SA. LF and MF observations of the lightning electromagnetic pulse at ionospheric altitudes. Geophysical Research Letters. 1997 Jan 1;24(9):1111–4.
• Cummer SA, Bell TF, Inan US, Zanetti LJ. VLF remote sensing of the auroral electrojet. Journal of Geophysical Research: Space Physics. 1996 Mar;101(A3):5381–9.
• Cummer SA. Another new FDTD method for linear dispersive media - but this one's the best yet. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). 1995 Jan 1;1:208–11.
• Bell TF, Inan US, Danielson MT, Cummer SA. VLF signatures of ionospheric heating by HIPAS. Radio Science. 1995 Jan 1;30(6):1855–67.
• Tian Z, Shen C, Li J, Reit E, Bachman H, Socolar J, et al. Dispersion Tuning and Route Reconfiguration of Acoustic Waves in Valley Topological Phononic Crystals (Accepted). Nature Communications.

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