Publications

O'Brien, C., B. M. Walsh, and E. G. Thomas (2025), Magnetosheath control of the cross polar cap potential: Correcting for measurement uncertainty in space weather, J. Geophys. Res. Space Physics, 130, e2024JA033468, doi:10.1029/2024JA033468.

de Abreu, A. J., E. Correia, O. F. Jonah, K. Venkatesh, E. G. Thomas, R. de Jesus, M. Roberto, J. R. Abalde, and P. R. Fagundes (2025), Observation and simulation studies of ionospheric F-region in the South American and Antarctic sectors during the intense space weather event of August 2018, J. Atmos. Sol.-Terr. Phys., 266, 106394, doi:10.1016/j.jastp.2024.106394.

Thomas, E. G., S. G. Shepherd, B. S. R. Kunduri, and D. R. Themens (2024), Multi-frequency SuperDARN HF radar observations of the ionospheric response to the October 2023 annular solar eclipse, Geophys. Res. Lett., 51, e2024GL112450, doi:10.1029/2024GL112450.

Kunduri, B. S. R., J. B. H. Baker, J. M. Ruohoniemi, E. G. Thomas, J. D. Huba, D. J. Emmons, D. R. Themens, K. T. Sterne, G. Farinas Perez, W. A. Bristow, S. G. Shepherd, J. M. Holmes, E. V. Dao, A. T. Chartier, G. W. Perry, and K. Pandey (2024), HF radar observations and modeling of the impact of the 8 April 2024 total solar eclipse on the ionosphere-thermosphere system, Geophys. Res. Lett., 51, e2024GL112484, doi:10.1029/2024GL112484.

Thomas, E. G., S. G. Shepherd, and G. Chisham (2024), Multi-frequency SuperDARN interferometer calibration, Radio Sci., 59, e2024RS007957, doi:10.1029/2024RS007957.

Walach, M.-T., A. Grocott, E. G. Thomas, and F. Staples (2022), Dusk-dawn asymmetries in SuperDARN convection maps, J. Geophys. Res. Space Physics, 127, e2022JA030906, doi:10.1029/2022JA030906.

Prikryl, P., R. G. Gillies, D. R. Themens, J. M. Weygand, E. G. Thomas, and S. Chakraborty (2022), Multi-instrument observations of polar cap patches and traveling ionospheric disturbances generated by solar wind Alfven waves coupling to the dayside magnetosphere, Ann. Geophys., 40, 619-639, doi:10.5194/angeo-40-619-2022.

Kunduri, B. S. R., J. B. H. Baker, J. M. Ruohoniemi, E. G. Thomas, and S. G. Shepherd (2022), An examination of SuperDARN backscatter modes using machine learning guided by ray-tracing, Space Weather, 20, e2022SW003130, doi:10.1029/2022SW003130.

Zhang, S.-R., Y. Nishimura, P. J. Erickson, E. Aa, H. Kil, Y. Deng, E. G. Thomas, W. Rideout, A. J. Coster, R. Kerr, and J. Vierinen (2022), Traveling ionospheric disturbances in the vicinity of storm enhanced density at midlatitudes, J. Geophys. Res. Space Physics, 127, e2022JA030429, doi:10.1029/2022JA030429.

Chisham, G., A. G. Burrell, E. G. Thomas, and Y.-J. Chen (2022), Ionospheric boundaries derived from auroral images, J. Geophys. Res. Space Physics, 127, e2022JA030622, doi:10.1029/2022JA030622.

Thomas, E. G., and S. G. Shepherd (2022), Virtual height characteristics of ionospheric and ground scatter observed by mid-latitude SuperDARN HF radars, Radio Sci., 57, e2022RS007429, doi:10.1029/2022RS007429.

Walach, M.-T., A. Grocott, F. Staples, and E. G. Thomas (2022), Super Dual Auroral Radar Network expansion and its influence on the derived ionospheric convection pattern, J. Geophys. Res. Space Physics, 127, e2021JA029559, doi:10.1029/2021JA029559.

Reistad, J. P., K. M. Laundal, N. Østgaard, A. Ohma, A. G. Burrell, S. M. Hatch, S. Haaland, and E. G. Thomas (2021), Quantifying the lobe reconnection rate during dominant IMF By periods and different dipole tilt orientations, J. Geophys. Res. Space Physics, 126, e2021JA029742, doi:10.1029/2021JA029742.

Yukimatu, A. S., A. Grocott, E. G. Thomas, T. Nagatsuma, N. Nishitani, K. Hosokawa, and M. Watanabe (2021), Editorial: Special issue: "SuperDARN / Studies of Geospace Dynamics - Today and Future", Polar Science, 28, 100690, doi:10.1016/j.polar.2021.100690.

Chisham, G., A. G. Burrell, A. Marchaudon, S. G. Shepherd, E. G. Thomas, and P. V. Ponomarenko (2021), Comparison of interferometer calibration techniques for improved SuperDARN elevation angles, Polar Science, 28, 100638, doi:10.1016/j.polar.2021.100638.

Shreedevi, P. R., R. K. Choudhary, S. V. Thampi, S. Yadav, T. K. Pant, Y. Yu, R. M. McGranaghan, E. G. Thomas, A. Bhardwaj, and A. K. Sinha (2020), Geomagnetic storm induced plasma density enhancements in the southern polar ionospheric region: a comparative study using St. Patrick's day storms of 2013 and 2015, Space Weather, 18, e2019SW002383, doi:10.1029/2019SW002383.

Shepherd, S. G., K. T. Sterne, E. G. Thomas, J. M. Ruohoniemi, J. B. H. Baker, R. T. Parris, T. R. Pedersen, and J. M. Holmes (2020), Bistatic observations with SuperDARN HF radars: First results, Radio Sci., 55, e2020RS007121, doi:10.1029/2020RS007121.

Fogg, A. R., M. Lester, T. K.Yeoman, A. G. Burrell, S. M. Imber, S. E. Milan, E. G. Thomas, H. Sangha, and B. J. Anderson (2020), An improved estimation of SuperDARN Heppner-Maynard Boundaries using AMPERE data, J. Geophys. Res. Space Physics, 125, e2019JA027218, doi:10.1029/2019JA027218.

Burrell, A. G., G. Chisham, S. E. Milan, L. Kilcommons, Y.-J. Chen, E. G. Thomas, and B. Anderson (2020), AMPERE polar cap boundaries, Ann. Geophys., 38, 481-490, doi:10.5194/angeo-38-481-2020.

Fæhn Follestad, A., L. B. N. Clausen, E. G. Thomas, Y. Jin, and A. J. Coster (2019), Polar cap patch prediction in the expanding contracting polar cap paradigm, Space Weather, 17, 1570-1583, doi:10.1029/2019SW002276.

Shore, R. M., M. P. Freeman, J. C. Coxon, E. G. Thomas, J. W. Gjerloev, and N. Olsen (2019), Spatial variation in the responses of the surface external and induced magnetic field to the solar wind, J. Geophys. Res. Space Physics, 124, 6195-6211, doi:10.1029/2019JA026543.

Reistad, J. P., K. M. Laundal, N. Østgaard, A. Ohma, E. G. Thomas, S. Haaland, K. Oksavik, and S. E. Milan (2019), Separation and quantification of ionospheric convection sources: 2. The dipole tilt angle influence on reverse convection cells during northward IMF, J. Geophys. Res. Space Physics, 124, 6182-6194, doi:10.1029/2019JA026641.

Shreedevi, P. R., R. K. Choudhary, Y. Yu, and E. G. Thomas (2019), Morphological study on the ionospheric variability at Bharati, a polar cusp station in the southern hemisphere, J. Atmos. Sol.-Terr. Phys., 193, 105058, doi:10.1016/j.jastp.2019.105058.

Nishitani, N., J. M. Ruohoniemi, M. Lester, J. B. H. Baker, A. V. Koustov, S. G. Shepherd, G. Chisham, T. Hori, E. G. Thomas, R. A. Makarevich, A. Marchaudon, P. Ponomarenko, J. A. Wild, S. E. Milan, W. A. Bristow, J. Devlin, E. Miller, R. A. Greenwald, T. Ogawa, and T. Kikuchi (2019), Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF radars, Prog Earth Planet Sci, 6:27, doi:10.1186/s40645-019-0270-5.

Priyadarshi, S., Q.-H. Zhang, E. G. Thomas, L. Spogli, and C. Cesaroni (2018), Polar traveling ionospheric disturbances inferred with the B-spline method and associated scintillations in the Southern Hemisphere, Adv. Space Res., 62, 3249-3266, doi:10.1016/j.asr.2018.08.015.

Thomas, E. G., and S. G. Shepherd (2018), Statistical patterns of ionospheric convection derived from mid-latitude, high-latitude, and polar SuperDARN HF radar observations, J. Geophys. Res. Space Physics, 123, 3196-3216, doi:10.1002/2018JA025280.

Correia, E., L. Spogli, L. Alfonsi, C. Cesaroni, A. M. Gulisano, E. G. Thomas, R. F. H. Ramirez, and A. A. Rodel (2017), Ionospheric F-region response to the 26 September 2011 geomagnetic storm in the Antarctic American and Australian sectors, Ann. Geophys., 35, 1113-1129, doi:10.5194/angeo-35-1113-2017.

Kunduri, B. S. R., J. B. H. Baker, J. M. Ruohoniemi, E. G. Thomas, S. G. Shepherd, and K. T. Sterne (2017), Statistical characterization of the large-scale structure of the subauroral polarization stream, J. Geophys. Res. Space Physics, 122, 6035-6048, doi:10.1002/2017JA024131.

Zou, S., A. J. Ridley, X. Jia, E. Boyd, M. J. Nicolls, A. J. Coster, E. G. Thomas, and J. M. Ruohoniemi (2017), PFISR observation of intense ion upflow fluxes associated with an SED during the 1 June 2013 geomagnetic storm, J. Geophys. Res. Space Physics, 122, 2589-2604, doi:10.1002/2016JA023697.

Prikryl, P., R. Ghoddousi-Fard, J. M. Weygand, A. Viljanen, M. Connors, D. W. Danskin, P. T. Jayachandran, K. S. Jacobsen, Y. L. Andalsvik, E. G. Thomas, J. M. Ruohoniemi, T. Durgonics, K. Oksavik, E. Spanswick, M. Aquino, and V. Sreeja (2016), GPS phase scintillation at high latitudes during the geomagnetic storm of March 17-18, 2015, J. Geophys. Res. Space Physics, 121, 10,448-10,465, doi:10.1002/2016JA023171.

Coster, A. J., P. J. Erickson, J. C. Foster, E. G. Thomas, J. M. Ruohoniemi, and J. B. H. Baker (2016), Solar Cycle 24 Observations of Storm Enhanced Density and the Tongue of Ionization, in Ionospheric Space Weather: Longitude and Hemispheric Dependencies and Lower Atmosphere Forcing (eds T. Fuller-Rowell, E. Yizengaw, P. H. Doherty, and S. Basu), John Wiley & Sons, Inc, Hoboken, NJ, doi:10.1002/9781118929216.ch6.

Zhang, Q.-H., J. Moen, M. Lockwood, I. McCrea, B.-C. Zhang, K. A. McWilliams, Q.-G. Zong, S.-R. Zhang, J. M. Ruohoniemi, E. G. Thomas, M. W. Dunlop, R.-Y. Liu, H. Yang, H.-Q. Hu, and M. Lester (2016), Polar cap patch transportation beyond the classic scenario, J. Geophys. Res. Space Physics, 121, 9063-9074, doi:10.1002/2016JA022443.

Zhang, Q.-H., M. Lockwood, R. Heelis, M. Hairston, J. Liang, I. McCrea, B.-C. Zhang, J. Moen, S.-R. Zhang, Y. Zhang, J. M. Ruohoniemi, M. Lester, E. G. Thomas, R.-Y. Liu, M. W. Dunlop, Y. Liu, and Y.-Z. Ma (2016), Earth's ion upflow associated with polar cap patches: Global and in situ observations, Geophys. Res. Lett., 43, 1845-1853, doi:10.1002/2016GL067897.

Thomas, E. G., J. B. H. Baker, J. M. Ruohoniemi, A. J. Coster, and S.-R. Zhang (2016), The geomagnetic storm time response of GPS total electron content in the North American sector, J. Geophys. Res. Space Physics, 121, 1744-1759, doi:10.1002/2015JA022182.

Prikryl, P., R. Ghoddousi-Fard, J. M. Ruohoniemi, and E. G. Thomas (2015), GPS Phase Scintillation at High Latitudes during Two Geomagnetic Storms, in Auroral Dynamics and Space Weather (eds Y. Zhang and L. J. Paxton), John Wiley & Sons, Inc, Hoboken, NJ, doi:10.1002/9781118978719.ch15.

Thomas, E. G., K. Hosokawa, J. Sakai, J. B. H. Baker, J. M. Ruohoniemi, S. Taguchi, K. Shiokawa, Y. Otsuka, A. J. Coster, J.-P. St.-Maurice, and K. A. McWilliams (2015), Multi-instrument, high-resolution imaging of polar cap patch transportation, Radio Sci., 50, 904-915, doi:10.1002/2015RS005672.

Joshi, P. P., J. B. H. Baker, J. M. Ruohoniemi, J. J. Makela, D. J. Fisher, B. J. Harding, N. A. Frissell, and E. G. Thomas (2015), Observations of storm time midlatitude ion-neutral coupling using SuperDARN radars and NATION Fabry-Perot interferometers, J. Geophys. Res. Space Physics, 120, 8989-9003, doi:10.1002/2015JA021475.

Liu, J., T. Nakamura, L. Liu, W. Wang, N. Balan, T. Nishiyama, M. R. hairston, and E. G. Thomas (2015), Formation of polar ionospheric tongue of ionization during minor geomagnetic disturbed conditions, J. Geophys. Res. Space Physics, 120, 6860-6873, doi:10.1002/2015JA021393.

Walsh, B. M., E. G. Thomas, K.-J. Hwang, J. B. H. Baker, J. M. Ruohoniemi, and J. W. Bonnell (2015), Dense plasma and Kelvin-Helmholtz waves at Earth's dayside magnetopause, J. Geophys. Res. Space Physics, 120, 5560-5573, doi:10.1002/2015JA021014.

Prikryl, P., R. Ghoddousi-Fard, L. Spogli, C. N. Mitchell, G. Li, B. Ning, P. J. Cilliers, V. Sreeja, M. Aquino, M. Terkildsen, P. T. Jayachandran, Y. Jiao, Y. T. Morton, J. M. Ruohoniemi, E. G. Thomas, Y. Zhang, A. T. Weatherwax, L. Alfonsi, G. De Franceschi, and V. Romano (2015), GPS phase scintillation at high latitudes during geomagnetic storms of 7-17 March 2012 - Part 2: Interhemispheric comparison, Ann. Geophys., 33, 657-670, doi:10.5194/angeo-33-657-2015.

Prikryl, P., R. Ghoddousi-Fard, E. G. Thomas, J. M. Ruohoniemi, S. G. Shepherd, P. T. Jayachandran, D. W. Danskin, E. Spanswick, Y. Zhang, Y. Jiao, and Y. T. Morton (2015), GPS phase scintillation at high latitudes during geomagnetic storms of 7-17 March 2012 - Part 1: The North American sector, Ann. Geophys., 33, 636-656, doi:10.5194/angeo-33-637-2015.

Zou, S., M. B. Moldwin, A. J. Ridley, M. J. Nicolls, A. J. Coster, E. G. Thomas, and J. M. Ruohoniemi (2014), On the generation/decay of the storm-enhanced density plumes: Role of the convection flow and field-aligned ion flow, J. Geophys. Res. Space Physics, 119, 8543-8559, doi:10.1002/2014JA020408.

Zou, S., A. J. Ridley, M. B. Moldwin, M. J. Nicolls, A. J. Coster, E. G. Thomas, and J. M. Ruohoniemi (2013), Multi-instrument observations of SED during 24-25 October 2011 storm: Implications for SED formation processes, J. Geophys. Res. Space Physics, 118, 7798-7809, doi:10.1002/2013JA018860.

Prikryl, P., R. Ghoddousi-Fard, B. S. R. Kunduri, E. G. Thomas, A. J. Coster, P. T. Jayachandran, E. Spanswick, and D. W. Danskin (2013), GPS phase scintillation and proxy index at high latitudes during a moderate geomagnetic storm, Ann. Geophys., 31, 805-816, doi:10.5194/angeo-31-805-2013.

Zhang, Q.-H., B.-C. Zhang, M. Lockwood, H.-Q. Hu, J. Moen, J. M. Ruohoniemi, E. G. Thomas, S.-R. Zhang, H.-G. Yang, R.-Y. Liu, K. A. McWilliams, and J. B. H. Baker (2013), Direct Observations of the Evolution of Polar Cap Ionization Patches, Science, 339, 1597-1600, doi:10.1126/science.1231487.

Thomas, E. G., J. B. H. Baker, J. M. Ruohoniemi, L. B. N. Clausen, A. J. Coster, J. C. Foster, and P. J. Erickson (2013), Direct observations of the role of convection electric field in the formation of a polar tongue of ionization from storm enhanced density, J. Geophys. Res. Space Physics, 118, 1180-1189, doi:10.1002/jgra.50116.

Kunduri, B. S. R., J. B. H. Baker, J. M. Ruohoniemi, L. B. N. Clausen, A. Grocott, E. G. Thomas, M. P. Freeman, and E. R. Talaat (2012), An examination of interhemispheric conjugacy in a sub-auroral polarization stream, J. Geophys. Res., 117, A08225, doi:10.1029/2012JA017784.

Clausen, L. B. N., J. B. H. Baker, J. M. Ruohoniemi, R. A. Greenwald, E. G. Thomas, S. G. Shepherd, E. R. Talaat, W. A. Bristow, Y. Zheng, A. J. Coster, and S. Sazykini (2012), Large-scale observations of a subauroral polarization stream by midlatitude SuperDARN radars: Instantaneous longitudinal velocity variations, J. Geophys. Res., 117, A05306, doi:10.1029/2011JA017232.