Research Interests
Space weather
Cometary plasma dynamics and Solar wind interaction
Earth's radiation belts
Geomagnetic storms and substorms
Solar wind-Magnetosphere-Ionosphere coupling
Auroral activity
Ionospheric irregularity
Ionosphere modeling
Positions
2023 December - present: Specially Appointed Professor (特任教授): University of Science of Technology of China (USTC), P. R. China
2023 January - 2023 November: CAS Distinguished Researcher: University of Science of Technology of China (USTC), P. R. China
2019 November - 2022 November: Ramanujan Fellow: Indian Institute of Technology Indore (IITI), India
2018 November - 2019 October: Ramanujan Fellow: National Atmospheric Research Laboratory (NARL), India
2016 March - 2018 October: Postdoctoral Fellow: Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Centre National de la Recherche Scientifique (CNRS), Orléans, France
2012 August - 2015 September: Postdoctoral Fellow: Divisão de Geofísica Espacial (DGE), Instituto Nacional de Pesquisas Espaciais (INPE), São Paulo, Brazil
Education
PhD (Space Physics): University of Calcutta 2012
MSc (Physics): University of Calcutta 2005
BSc (Physics): University of Calcutta 2003
Publications - refereed journals
85. Hajra, R., B. T. Tsurutani, Q. Lu, R. B. Horne, G. S. Lakhina, X. Yang, P. Henri, A. Du, X. Gao, R. Wang, and S. Lu (2024), The April 2023 SYM-H = –233 nT Geomagnetic Storm: A Classical Event, Journal of Geophysical Research: Space Physics (under revision).
84. Tsurutani, B. T., R. Hajra, G. Lakhina, and X. Meng (2024), Comment to “The Solar and Interplanetary Causes of Superstorms (Minimum Dst ≤ -250 nT) During the Space Age” by Meng et al. 2019, J. Geophys. Res. Space Phys.: An Extraordinary CIR Caused Superstorm on 6-7 April 2000, Journal of Geophysical Research: Space Physics (under revision).
83. Hajra, R., B. T. Tsurutani, G. S. Lakhina, Q. Lu, and A. Du (2024), Interplanetary Causes and Impacts of the 2024 May Superstorm on the Geosphere: An Overview, The Astrophysical Journal (accepted), https://doi.org/10.3847/1538-4357/ad7462.
82. Oliveira, D. M., R. C. Allen, L. R. Alves, S. P. Blake, B. A. Carter, D. Chakrabarty, G. D’Angelo, K. Delano, E. Echer, C. P. Ferradas, M. G. Finley, B. Gallardo-Lacourt, D. Gershman, J. W. Gjerloev, J. B. Habarulema, M. D. Hartinger, R. Hajra, H. Hayakawa, L. Juusola, K. M. Laundal, R. J. Leamon, M. Madelaire, M. Martínez-Ledesma, S. M. McIntosh, Y. Miyoshi, M. B. Moldwin, E. Nahayo, D. Nandy, B. Nilam, K. Nykyri, W. R. Paterson, M. Piersanti, E. Pietropaolo, C. J. Rodger, T. Shah, A. W. Smith, N. Srivastava, B. T. Tsurutani, S. Tulasi Ram, L. A. Upton, B. Veenadhari, S. Vidal-Luengo, A. Viljanen, S. K. Vines, V. K. Yadav, J.-H. Yee, J. W. Weygand, and E. Zesta (2024), Predicting interplanetary shock occurrence for solar cycle 25: Opportunities and challenges in space weather research, Space Weather, 22, e2024SW003964, https://doi.org/10.1029/2024SW003964.
81. Despirak, I., P. Setsko, A. Lubchich, R. Hajra, Y. Sakharov, G. Lakhina, V. Selivanov, and B. T. Tsurutani (2024), Geomagnetically induced currents (GICs) during strong geomagnetic activity (storms, substorms, and magnetic pulsations) on 23–24 April 2023, Journal of Atmospheric and Solar-Terrestrial Physics, 261, 106293, https://doi.org/10.1016/j.jastp.2024.106293.
80. Tsurutani, B. T., A. Sen, R. Hajra, G. S. Lakhina, R. B. Horne, and T. Hada (2024), Review of the August 1972 and March 1989 (Allen) Space Weather Events: Can We Learn Anything New From Them?, Journal of Geophysical Research: Space Physics, 129, e2024JA032622, https://doi.org/10.1029/2024JA032622.
79. Zhou, X., X. Gao, Q. Lu, R. Hajra, Y. Ke, R. Chen, and J. Ma (2024), Prompt disappearance of magnetospheric chorus waves caused by high-speed magnetosheath jets, Journal of Geophysical Research: Space Physics, 129, e2024JA032576, https://doi.org/10.1029/2024JA032576.
78. Hajra, R., B. T. Tsurutani, Q. Lu, G. S. Lakhina, A. Du, E. Echer, A. M. S. Franco, M. J. A. Bolzan, and X. Gao (2024), Ultra-relativistic Electron Acceleration during High-Intensity Long-Duration Continuous Auroral Electrojet (AE) Activity (HILDCAA) Events, The Astrophysical Journal, 965: 146, https://doi.org/10.3847/1538-4357/ad2dfe.
77. Jones, G. H., C. Snodgrass, C. Tubiana, M. Küppers, H. Kawakita, L. M. Lara, J. Agarwal, N. André, N. Attree, U. Auster, S. Bagnulo, M. Bannister, A. Beth, N. Bowles, A. Coates, L. Colangeli, C. C. van Damme, V. Da Deppo, J. De Keyser, V. Della Corte, N. Edberg, M. R. El-Maarry, S. Faggi, M. Fulle, R. Funase, M. Galand, C. Goetz, O. Groussin, A. Guilbert-Lepoutre, P. Henri, S. Kasahara, A. Kereszturi, M. Kidger, M. Knight, R. Kokotanekova, I. Kolmasova, K. Kossacki, E. Kührt, Y. Kwon, F. La Forgia, A.-C. Levasseur-Regourd, M. Lippi, A. Longobardo, R. Marschall, M. Morawski, O. Muñoz, A. Näsilä, H. Nilsson, C. Opitom, M. Pajusalu, A. Pommerol, L. Prech, N. Rando, F. Ratti, H. Rothkaehl, A. Rotundi, M. Rubin, N. Sakatani, J. P. Sánchez, C. S. Wedlund, A. Stankov, N. Thomas, I. Toth, G. Villanueva, J.-B. Vincent, M. Volwerk, P. Wurz, A. Wielders, K. Yoshioka, K. Aleksiejuk, F. Alvarez, C. Amoros, S. Aslam, B. Atamaniuk, J. Baran, T. Barciński, T. Beck, T. Behnke, M. Berglund, I. Bertini, M. Bieda, P. Binczyk, M.-D. Busch, A. Cacovean, M. T. Capria, C. Carr, J. M. C. Marín, M. Ceriotti, P. Chioetto, A. Chuchra-Konrad, L. Cocola, F. Colin, C. Crews, V. Cripps, E. Cupido, A. Dassatti, B. J. R. Davidsson, T. De Roche, J. Deca, S. Del Togno, F. Dhooghe, K. D. Hanna, A. Eriksson, A. Fedorov, E. Fernández-Valenzuela, S. Ferretti, J. Floriot, F. Frassetto, J. Fredriksson, P. Garnier, D. Gaweł, V. Génot, T. Gerber, K.-H. Glassmeier, M. Granvik, B. Grison, H. Gunell, T. Hachemi, C. Hagen, R. Hajra, Y. Harada, J. Hasiba, N. Haslebacher, M. L. H. De La Revilla, D. Hestroffer, T. Hewagama, C. Holt, S. Hviid, I. Iakubivskyi, L. Inno, P. Irwin, S. Ivanovski, J. Jansky, I. Jernej, H. Jeszenszky, J. Jimenéz, L. Jorda, M. Kama, S. Kameda, M. S. P. Kelley, K. Klepacki, T. Kohout, H. Kojima, T. Kowalski, M. Kuwabara, M. Ladno, G. Laky, H. Lammer, R. Lan, B. Lavraud, M. Lazzarin, O. Le Duff, Q.-M. Lee, C. Lesniak, Z. Lewis, Z.-Y. Lin, T. Lister, S. Lowry, W. Magnes, J. Markkanen, I. M. Navajas, Z. Martins, A. Matsuoka, B. Matyjasiak, C. Mazelle, E. M. Epifani, M. Meier, H. Michaelis, M. Micheli, A. Migliorini, A.-L. Millet, F. Moreno, S. Mottola, B. Moutounaick, K. Muinonen, D. R. Müller, G. Murakami, N. Murata, K. Myszka, S. Nakajima, Z. Nemeth, A. Nikolajev, S. Nordera, D. Ohlsson, A. Olesk, H. Ottacher, N. Ozaki, C. Oziol, M. Patel, A. S. Paul, A. Penttilä, C. Pernechele, J. Peterson, E. Petraglio, A. M. Piccirillo, F. Plaschke, S. Polak, F. Postberg, H. Proosa, S. Protopapa, W. Puccio, S. Ranvier, S. Raymond, I. Richter, M. Rieder, R. Rigamonti, I. R. Rodriguez, O. Santolik, T. Sasaki, R. Schrödter, K. Shirley, A. Slavinskis, B. Sodor, J. Soucek, P. Stephenson, L. Stöckli, P. Szewczyk, G. Troznai, L. Uhlir, N. Usami, A. Valavanoglou, J. Vaverka, W. Wang, X.-D. Wang, G. Wattieaux, M. Wieser, S. Wolf, H. Yano, I. Yoshikawa, V. Zakharov, T. Zawistowski, P. Zuppella, G. Rinaldi, and H. Ji (2024), The Comet Interceptor Mission, Space Science Reviews, 220: 9, https://doi.org/10.1007/s11214-023-01035-0.
76. Guo, J., S. Lu, Q. Lu, J. A. Slavin, W. Sun, J. Ren, X. Wang, Y. Lin, R. Hajra, and R. Wang (2023), Three-Dimensional Global Hybrid Simulations of Mercury's Disappearing Dayside Magnetosphere, Journal of Geophysical Research: Planets, 128, e2023JE008032, https://doi.org/10.1029/2023JE008032.
75. Hajra, R., B. T. Tsurutani, Q. Lu, L. Shan, A. Du, R. Wang, S. Lu, and X. Gao (2023), Extreme Rarefaction of Solar Wind: A Study on Origin and Characteristics using Ulysses Observations, The Astrophysical Journal, 955: 120, https://doi.org/10.3847/1538-4357/acf45c.
74. Tsurutani, B. T., G. P. Zank, V. J. Sterken, K. Shibata, T. Nagai, A. J. Mannucci, D. M. Malaspina, G. S. Lakhina, S. G. Kanekal, K. Hosokawa, R. B. Horne, R. Hajra, K. H. Glassmeier, C. T. Gaunt, P. F. Chen, and S. I. Akasofu (2023), Space Plasma Physics: A Review, IEEE Transactions on Plasma Science, 51, 1595-1655, https://doi.org/10.1109/TPS.2022.3208906.
73. Hajra, R., B. T. Tsurutani, G. S. Lakhina, Q. Lu, A. Du, and L. Shan (2023), Interplanetary Shocks between 0.3 and 1.0 au: Helios 1 and 2 Observations, The Astrophysical Journal, 951: 75, https://doi.org/10.3847/1538-4357/acd370.
72. Hajra, R., E. Echer, A. M. S. Franco, and M. J. A. Bolzan (2023), Earth’s magnetotail variability during supersubstorms (SSSs): A study on solar wind–magnetosphere–ionosphere coupling, Advances in Space Research, 72, 1208-1223, https://doi.org/10.1016/j.asr.2023.04.013.
71. Tsurutani, B. T., G. S. Lakhina, and R. Hajra (2023), Comments on “New Insights From the 2003 Halloween Storm Into the Colaba 1600 nT Magnetic Depression During the 1859 Carrington Storm” by S. Ohtani (2022), Journal of Geophysical Research: Space Physics, 128, e2022JA031034, https://doi.org/10.1029/2022JA031034.
70. Echer, E., A. Lucas, R. Hajra, A. M. S. Franco, M. J. A. Bolzan, and L. E. S. Nascimento (2023), Geomagnetic Activity Following Interplanetary Shocks in Solar Cycles 23 and 24, Brazilian Journal of Physics, 53: 79, https://doi.org/10.1007/s13538-023-01294-w.
69. Hajra, R. (2023), Near-Earth High-Speed and Slow Solar Winds: A Statistical Study on Their Characteristics and Geomagnetic Impacts, Solar Physics, 298: 53, https://doi.org/10.1007/s11207-023-02141-6.
68. Tsurutani, B. T., and R. Hajra (2023), Energetics of Shock Triggered Supersubstorms (SML < -2500 nT), The Astrophysical Journal, 946: 17, https://doi.org/10.3847/1538-4357/acb143.
67. Echer, E., A. M. S. Franco, F. P. Magalhães, M. J. A. Bolzan, and R. Hajra (2023), Study of Neptune dayside magnetosheath fluctuations during Voyager-2 flyby, Advances in Space Research, 71, 3468-3478, https://doi.org/10.1016/j.asr.2022.12.022.
66. Sunny, J. V., A. G. Nair, M. Babu, and R. Hajra (2023), A Comparative Study on Geoeffective and Non-geoeffective Corotating Interaction Regions, Advances in Space Research, 71, 268-274, https://doi.org/10.1016/j.asr.2022.09.051.
65. Echer, E., A. M. S. Franco, E. C. Junior, R. Hajra, and M. J. A. Bolzan (2022), Solar-Wind High-Speed Stream (HSS) Alfvén Wave Fluctuations at High Heliospheric Latitudes: Ulysses Observations During Two Solar-Cycle Minima, Solar Physics, 297: 143, https://doi.org/10.1007/s11207-022-02070-w.
64. Tsurutani, B. T., and R. Hajra (2022), Extremely Slow (Vsw < 300 km s−1) Solar Winds (ESSWs) at 1 au: Causes of Extreme Geomagnetic Quiet at Earth, The Astrophysical Journal, 936: 155, https://doi.org/10.3847/1538-4357/ac7444.
63. Chen, R., B. T. Tsurutani, X. Gao, Q. Lu, H. Chen, G. S. Lakhina, and R. Hajra (2022), The Structure and Microstructure of Rising-tone Chorus with Frequencies Crossing at f ∼ 0.5 fce, Journal of Geophysical Research: Space Physics, 127, e2022JA030438, https://doi.org/10.1029/2022JA030438.
62. Hajra, R., J. V. Sunny, M. Babu, and A. G. Nair (2022), Interplanetary Sheaths and Corotating Interaction Regions: A Comparative Statistical Study on Their Characteristics and Geoeffectiveness, Solar Physics, 297: 97, https://doi.org/10.1007/s11207-022-02020-6.
61. Bolzan, M. J. A., E. Echer, A. M. S. Franco, and R. Hajra (2022), Identification of the planetary magnetosphere boundaries with the wavelet multi-resolution analysis, Journal of Atmospheric and Solar-Terrestrial Physics, 230, 105842, https://doi.org/10.1016/j.jastp.2022.105842.
60. Hajra, R., and J. V. Sunny (2022), Corotating Interaction Regions during Solar Cycle 24: A Study on Characteristics and Geoeffectiveness, Solar Physics, 297: 30, https://doi.org/10.1007/s11207-022-01962-1.
59. Hajra, R., and B. T. Tsurutani (2022), Near-Earth Sub-Alfvénic Solar Winds: Interplanetary Origins and Geomagnetic Impacts, The Astrophysical Journal, 926: 135, https://doi.org/10.3847/1538-4357/ac4471.
58. Goetz, C., H. Gunell, M. Volwerk, A. Beth, A. Eriksson, M. Galand, P. Henri, H. Nilsson, C. S. Wedlund, M. Alho, L. Andersson, N. Andre, J. De Keyser, J. Deca, Y. Ge, K.-H. Glassmeier, R. Hajra, T. Karlsson, S. Kasahara, I. Kolmasova, K. LLera, H. Madanian, I. Mann, C. Mazelle, E. Odelstad, F. Plaschke, M. Rubin, B. Sanchez-Cano, C. Snodgrass, and E. Vigren (2022), Cometary plasma science: Open science questions for future space missions, Experimental Astronomy, 54, 1129-1167, https://doi.org/10.1007/s10686-021-09783-z.
57. Hajra, R. (2022), Intense Geomagnetically Induced Currents (GICs): Association with Solar and Geomagnetic Activities, Solar Physics, 297: 14, https://doi.org/10.1007/s11207-021-01945-8.
56. Hajra, R. (2022), Intense, long-duration geomagnetically induced currents (GICs) caused by intense substorm clusters, Space Weather, 20, e2021SW002937, https://doi.org/10.1029/2021SW002937.
55. Franco, A. M. S., R. Hajra, E. Echer, and M. J. A. Bolzan (2021), Seasonal features of geomagnetic activity: a study on the solar activity dependence, Annales Geophysicae, 39, 929-943, https://doi.org/10.5194/angeo-39-929-2021.
54. Hajra, R. (2021), Variation of the interplanetary shocks in the inner heliosphere, The Astrophysical Journal, 917: 91, https://doi.org/10.3847/1538-4357/ac0897.
53. Tsurutani, B. T., and R. Hajra (2021), The Interplanetary and Magnetospheric causes of Geomagnetically Induced Currents (GICs) > 10 A in the Mäntsälä Finland Pipeline: 1999 through 2019 – Erratum, Journal of Space Weather and Space Climate, 11, 32, https://doi.org/10.1051/swsc/2021015.
52. Hajra, R., A. M. de Souza Franco, E. Echer, and M. J. A. Bolzan (2021), Long‐Term Variations of the Geomagnetic Activity: A Comparison Between the Strong and Weak Solar Activity Cycles and Implications for the Space Climate, Journal of Geophysical Research: Space Physics, 126, e2020JA028695, https://doi.org/10.1029/2020JA028695.
51. Tsurutani, B. T., and R. Hajra (2021), The Interplanetary and Magnetospheric causes of Geomagnetically Induced Currents (GICs) > 10 A in the Mäntsälä Finland Pipeline: 1999 through 2019, Journal of Space Weather and Space Climate, 11, 23, https://doi.org/10.1051/swsc/2021001.
50. Hajra, R. (2021), September 2017 Space-Weather Events: A Study on Magnetic Reconnection and Geoeffectiveness, Solar Physics, 296: 50, https://doi.org/10.1007/s11207-021-01803-7.
49. Hajra, R. (2021), Seasonal dependence of the Earth’s radiation belt – new insights, Annales Geophysicae, 39, 181-187, https://doi.org/10.5194/angeo-39-181-2021.
48. Hajra, R. (2021), Weakest Solar Cycle of the Space Age: A Study on Solar Wind-Magnetosphere Energy Coupling and Geomagnetic Activity, Solar Physics, 296: 33, https://doi.org/10.1007/s11207-021-01774-9.
47. Tsurutani, B. T., R. Chen, X. Gao, Q. Lu, J. S. Pickett, G. S. Lakhina, A. Sen, R. Hajra, S. A. Park, and B. J. Falkowski (2020), Lower-Band “Monochromatic” Chorus Riser Subelement/Wave Packet Observations, Journal of Geophysical Research: Space Physics, 125, e2020JA028090, https://doi.org/10.1029/2020JA028090.
46. Hajra, R., B. T. Tsurutani, and G. S. Lakhina (2020), The Complex Space Weather Events of 2017 September, The Astrophysical Journal, 899: 3, https://doi.org/10.3847/1538-4357/aba2c5.
45. Nemeth, Z., A. Timar, K. Szego, P. Henri, R. Hajra, and G. Wattieaux (2020), Plasma distribution around comet 67P in the last month of the Rosetta Mission, Icarus, 350, 113924, https://doi.org/10.1016/j.icarus.2020.113924.
44. Hajra, R., P. Henri, X. Vallières, M. Galand, M. Rubin, B. T. Tsurutani, N. Gilet, L. Bucciantini, and Z. Nemeth (2020), Ionospheric total electron content of comet 67P/Churyumov-Gerasimenko, Astronomy & Astrophysics, 635, A51, https://doi.org/10.1051/0004-6361/201937022.
43. Tsurutani, B. T., G. S. Lakhina, and R. Hajra (2020), The physics of space weather/solar-terrestrial physics (STP): what we know now and what the current and future challenges are, Nonlinear Processes in Geophysics, 27, 75-119, https://doi.org/10.5194/npg-27-75-2020.
42. Tsurutani, B. T., S. A. Park, B. J. Falkowski, J. Bortnik, G. S. Lakhina, A. Sen, J. S. Pickett, R. Hajra, M. Parrot, and P. Henri (2019), Low Frequency (f < 200 Hz) Polar Plasmaspheric Hiss: Coherent and Intense, Journal of Geophysical Research: Space Physics, 124, 10063-10084, https://doi.org/10.1029/2019JA027102.
41. Tsurutani, B. T., R. Hajra, E. Echer, and G. S. Lakhina (2019), Comment on “First Observation of Mesosphere Response to the Solar Wind High‐Speed Streams” by W. Yi et al., Journal of Geophysical Research: Space Physics, 124, 8165-8168, https://doi.org/10.1029/2018JA026447.
40. Breuillard, H., P. Henri, L. Bucciantini, M. Volwerk, T. Karlsson, A. Eriksson, F. Johansson, E. Odelstad, I. Richter, C. Goetz, X. Vallières, and R. Hajra (2019), The properties of the singing comet waves in the 67P/Churyumov-Gerasimenko plasma environment as observed by the Rosetta mission, Astronomy & Astrophysics, 630, A39, https://doi.org/10.1051/0004-6361/201834876.
39. Edberg, N. J. T., F. L. Johansson, A. I. Eriksson, D. J. Andrews, R. Hajra, P. Henri, C. Simon Wedlund, M. Alho, and E. Thiemann (2019), Solar flares observed by Rosetta at comet 67P/Churyumov-Gerasimenko, Astronomy & Astrophysics, 630, A49, https://doi.org/10.1051/0004-6361/201834834.
38. Tsurutani, B. T., S. A. Park, B. J. Falkowski, G. S. Lakhina, J. S. Pickett, J. Bortnik, G. Hospodarsky, O. Santolik, M. Parrot, P. Henri, and R. Hajra (2018), Plasmaspheric hiss: coherent and intense, Journal of Geophysical Research: Space Physics, 123, 10009-10029, https://doi.org/10.1029/2018JA025975.
37. Hajra, R., P. Henri, M. Myllys, K. L. Héritier, M. Galand, C. Simon Wedlund, H. Breuillard, E. Behar, N. J. T. Edberg, C. Goetz, H. Nilsson, A. I. Eriksson, R. Goldstein, B. T. Tsurutani, J. Moré, X. Vallières, and G. Wattieaux (2018), Cometary plasma response to interplanetary corotating interaction regions during 2016 June – September: a quantitative study by the Rosetta Plasma Consortium, Monthly Notices of the Royal Astronomical Society, 480, 4544-4556, https://doi.org/10.1093/mnras/sty2166.
36. Heritier, K. L., M. Galand, P. Henri, F. L. Johansson, A. Beth, A. I. Eriksson, X. Vallières, K. Altwegg, J. L. Burch, C. Carr, E. Ducrot, R. Hajra, and M. Rubin (2018), Plasma source and loss at comet 67P during the Rosetta mission, Astronomy & Astrophysics, 618, A77, https://doi.org/10.1051/0004-6361/201832881.
35. Hajra, R., and B. T. Tsurutani (2018), Interplanetary shocks inducing magnetospheric supersubstorms (SML < -2500 nT): unusual auroral morphologies and energy flow, The Astrophysical Journal, 858: 123, https://doi.org/10.3847/1538-4357/aabaed.
34. Engelhardt, I. A. D., A. I. Eriksson, G. Stenberg Wieser, C. Goetz, M. Rubin, P. Henri, H. Nilsson, E. Odelstad, R. Hajra, and X. Vallières (2018), Plasma density structures at comet 67P/Churyumov-Gerasimenko, Monthly Notices of the Royal Astronomical Society, 477, 1296-1307, https://doi.org/10.1093/mnras/sty765.
33. Hajra, R., P. Henri, X. Vallières, J. More, N. Gilet, G. Wattieaux, C. Goetz, I. Richter, B. T. Tsurutani, H. Gunell, H. Nilsson, A. I. Eriksson, Z. Nemeth, J. L. Burch, and M. Rubin ( 2018), Dynamic unmagnetized plasma in the diamagnetic cavity around comet 67P/Churyumov-Gerasimenko, Monthly Notices of the Royal Astronomical Society, 475, 4140-4147, https://doi.org/10.1093/mnras/sty094.
32. Tsurutani, B. T., G. S. Lakhina, E. Echer, R. Hajra, C. Nayak, A. J. Mannucci, and X. Meng (2018), Comment on “Modeling extreme “Carrington-type” space weather events using three-dimensional global MHD simulations” by C.M. Ngwira, A. Pulkkinen, M.M. Kuznetsova and A. Glocer, Journal of Geophysical Research: Space Physics, 123, 1388-1392, https://doi.org/10.1002/2017JA024779.
31. Souza, A. M., E. Echer, M. J. A. Bolzan, and R. Hajra (2018), Cross-correlation and cross-wavelet analyses of the solar wind IMF Bz and auroral electrojet index AE coupling during HILDCAAs, Annales Geophysicae, 36, 205-211, https://doi.org/10.5194/angeo-36-205-2018.
30. Guarnieri, F. L., B. T. Tsurutani, L. E. A. Vieira, R. Hajra, E. Echer, A. J. Mannucci, and W. D. Gonzalez (2018), A correlation study regarding the AE index and ACE solar wind data for Alfvénic intervals using wavelet decomposition and reconstruction, Nonlinear Processes in Geophysics, 25, 67-76, https://doi.org/10.5194/npg-25-67-2018.
29. Hajra, R., B. T. Tsurutani, C. G. M. Brum, and E. Echer (2017), High-speed solar wind stream effects on the topside ionosphere over Arecibo: A case study during solar minimum, Geophysical Research Letters, 44, 7607-7617, https://doi.org/10.1002/2017GL073805.
28. Hajra, R., P. Henri, X. Vallières, M. Galand, K. Héritier, A. I. Eriksson, E. Odelstad, N. J. T. Edberg, J. L. Burch, T. Broiles, R. Goldstein, K. H. Glassmeier, I. Richter, C. Goetz, B. T. Tsurutani, H. Nilsson, K. Altwegg, and M. Rubin (2017), Impact of a cometary outburst on its ionosphere – Rosetta Plasma Consortium observations of the outburst exhibited by comet 67P/Churyumov-Gerasimenko on 19 February 2016, Astronomy & Astrophysics, 607, A34, https://doi.org/10.1051/0004-6361/201730591.
27. Henri, P., X. Vallières, R. Hajra, C. Goetz, I. Richter, K.-H. Glassmeier, M. Galand, M. Rubin, A. I. Eriksson, Z. Nemeth, E. Vigren, A. Beth, J. L. Burch, C. Carr, H. Nilsson, B. T. Tsurutani, and G. Wattieaux (2017), Diamagnetic region(s): structure of the unmagnetised plasma around comet 67P/CG, Monthly Notices of the Royal Astronomical Society, 469, S372-S379, https://doi.org/10.1093/mnras/stx1540.
26. Mendes, O., M. O. Domingues, E. Echer, R. Hajra, and V. E. Menconi (2017), Characterization of high-intensity, long-duration continuous auroral activity (HILDCAA) events using recurrence quantification analysis, Nonlinear Processes in Geophysics, 24, 407-417, https://doi.org/10.5194/npg-24-407-2017.
25. Souza, A. M., E. Echer, M. J. A. Bolzan, and R. Hajra (2016), A study on the main periodicities in interplanetary magnetic field Bz component and geomagnetic AE index during HILDCAA events using wavelet analysis, Journal of Atmospheric and Solar-Terrestrial Physics, 149, 81-86, https://doi.org/10.1016/j.jastp.2016.09.006.
24. Tsurutani, B. T., R. Hajra, T. Tanimori, A. Takada, R. Bhanu, A. J. Mannucci, G. S. Lakhina, J. U. Kozyra, K. Shiokawa, L. C. Lee, E. Echer, R. V. Reddy, and W. D. Gonzalez (2016), Heliospheric plasma sheet (HPS) impingement onto the magnetosphere as a cause of relativistic electron dropouts (REDs) via coherent EMIC wave scattering with possible consequences for climate change mechanisms, Journal of Geophysical Research: Space Physics, 121, 10130-10156, https://doi.org/10.1002/2016JA022499.
23. Hajra, R., B. T. Tsurutani, E. Echer, W. D. Gonzalez, and J. W. Gjerloev (2016), Supersubstorms (SML < -2500 nT): magnetic storm and solar cycle dependences, Journal of Geophysical Research: Space Physics, 121, 7805-7816, https://doi.org/10.1002/2015JA021835.
22. Hajra, R., S. K. Chakraborty, B. T. Tsurutani, A. DasGupta, E. Echer, C. G. M. Brum, W. D. Gonzalez, and J. H. A. Sobral (2016), An empirical model of ionospheric total electron content (TEC) near the crest of the equatorial ionization anomaly (EIA), Journal of Space Weather and Space Climate, 6, A29, https://doi.org/10.1051/swsc/2016023.
21. Da Silva, L. A., P. Satyamurty, L. R. Alves, V. M. Souza, P. R. Jauer, M. V. D. Silveira, M. S. Echer, R. Hajra, C. Medeiros, J. P. Marchezi, M. Rockenbach, N. R. Rigozo, C. M. Denardini, O. Mendes Jr., A. Dal Lago, and L. E. A. Vieira (2016), Comparison of geophysical patterns in the southern hemisphere mid-latitude region, Advances in Space Research, 58, 2090-2103, https://doi.org/10.1016/j.asr.2016.04.003.
20. Verkhoglyadova, O. P., X. Meng, A. J. Mannucci, B. T. Tsurutani, L. A. Hunt, M. G. Mlynczak, R. Hajra, and B. A. Emery (2016), Estimation of energy budget of ionosphere-thermosphere system during two CIR-HSS events: observations and modeling, Journal of Space Weather and Space Climate, 6, A20, https://doi.org/10.1051/swsc/2016013.
19. Remya, B., B. T. Tsurutani, R. V. Reddy, G. S. Lakhina, and R. Hajra (2015), Electromagnetic cyclotron waves in the dayside subsolar outer magnetosphere generated by enhanced solar wind pressure: EMIC wave coherency, Journal of Geophysical Research: Space Physics, 120, 7536-7551, https://doi.org/10.1002/2015JA021327.
18. Hajra, R., B. T. Tsurutani, E. Echer, W. D. Gonzalez, C. G. M. Brum, and L. E. A. Vieira, and O. Santolik (2015), Relativistic electron acceleration during HILDCAA events: are precursor CIR magnetic storms important?, Earth, Planets and Space, 67, 109, https://doi.org/10.1186/s40623-015-0280-5.
17. Tsurutani, B. T., R. Hajra, E. Echer, and J. W. Gjerloev (2015), Extremely intense (SML ≤ -2500 nT) substorms: isolated events that are externally triggered?, Annales Geophysicae Communicates, 33, 519-524, https://doi.org/10.5194/angeo-33-519-2015.
16. Mannucci, A. J., O. P. Verkhoglyadova, B. T. Tsurutani, X. Meng, X. Pi, C. Wang, G. Rosen, E. Lynch, S. Sharma, A. Ridley, W. Manchester, B. Van Der Holst, E. Echer, and R. Hajra (2015), Medium-range thermosphere-ionosphere storm forecasts, Space Weather, 13, 125-129, https://doi.org/10.1002/2014SW001125.
15. Hajra, R., B. T. Tsurutani, E. Echer, W. D. Gonzalez, and O. Santolik (2015), Relativistic (E > 0.6, > 2.0 and > 4.0 MeV) electron acceleration at geosynchronous orbit during high-intensity long-duration continuous AE activity (HILDCAA) events, The Astrophysical Journal, 799: 39, https://doi.org/10.1088/0004-637X/799/1/39.
14. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez (2014), Superposed epoch analyses of HILDCAAs and their interplanetary drivers: solar cycle and seasonal dependences, Journal of Atmospheric and Solar-Terrestrial Physics, 121, 24-31, https://doi.org/10.1016/j.jastp.2014.09.012.
13. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez (2014), Relativistic electron acceleration during High-Intensity Long-duration Continuous AE Activity (HILDCAA) events: solar cycle phase dependences, Geophysical Research Letters, 41, 1876-1881, https://doi.org/10.1002/2014GL059383.
12. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez (2014), Solar wind-magnetosphere energy coupling efficiency and partitioning: HILDCAAs and preceding CIR-storms during solar cycle 23, Journal of Geophysical Research: Space Physics, 119, 2675-2690, https://doi.org/10.1002/2013JA019646.
11. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez (2013), Solar cycle dependence of High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events, relativistic electron predictors?, Journal of Geophysical Research: Space Physics, 118, 5626-5638, https://doi.org/10.1002/jgra.50530.
10. Hajra, R., S. K. Chakraborty, S. Mazumdar, and S. Alex (2012), Evolution of equatorial irregularities under varying electrodynamical conditions: a multi-technique case study from Indian longitude zone, Journal of Geophysical Research: Space Physics, 117, A08331, https://doi.org/10.1029/2012JA017808.
9. Chakraborty, S. K., R. Hajra, and A. DasGupta (2012), Ionospheric scintillation near the anomaly crest in relation to the variability of ambient ionization, Radio Science, 47, RS2006, https://doi.org/10.1029/2011RS004942.
8. Hajra, R., and S. K. Chakraborty (2011), Equatorial ionospheric responses in relation to the occurrence of main phase of intense geomagnetic storms in the local dusk sector, Journal of Atmospheric and Solar-Terrestrial Physics, 73, 760-770, https://doi.org/10.1016/j.jastp.2011.02.014.
7. Hajra, R., S. K. Chakraborty, and A. DasGupta (2010), Ionospheric effects near the magnetic equator and the anomaly crest of the Indian longitude zone during a large number of intense geomagnetic storms, Journal of Atmospheric and Solar-Terrestrial Physics, 72, 1299-1308, https://doi.org/10.1016/j.jastp.2010.09.015.
6. Chakraborty, S. K., and R. Hajra (2010), Variability of Total Electron Content near the crest of the equatorial anomaly during moderate geomagnetic storms, Journal of Atmospheric and Solar-Terrestrial Physics, 72, 900-911, https://doi.org/10.1016/j.jastp.2010.05.006.
5. Hajra, R., S. K. Chakraborty, and A. Paul (2009), Electrodynamical control of the ambient ionization near the equatorial anomaly crest in the Indian zone during counter-electrojet days, Radio Science, 44, RS3009, https://doi.org/10.1029/2008RS003904.
4. Chakraborty, S. K., and R. Hajra (2009), Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone, Annales Geophysicae, 27, 93-105, https://doi.org/10.5194/angeo-27-93-2009.
3. Chakraborty, S. K., R. Hajra, and A. Paul (2008), Ionosphere near the anomaly crest in Indian zone during magnetic storm on 13-14 March 1989, Indian Journal of Radio & Space Physics, 37, 396-407, http://nopr.niscair.res.in/handle/123456789/2775.
2. Chakraborty, S. K., and R. Hajra (2008), Solar control of ambient ionization of the ionosphere near the crest of the equatorial anomaly in the Indian zone, Annales Geophysicae, 26, 47-57, https://doi.org/10.5194/angeo-26-47-2008.
1. Chakraborty, S. K., and R. Hajra (2007), Solar control of ambient ionization of the ionosphere near the crest of the equatorial anomaly in the Indian zone, Bulletin of the Astronomical Society of India, 35, 599-605, http://www.ncra.tifr.res.in:8081/~basi/07December/355992007.PDF.
Publications - book chapters
2. Lakhina, G. S., R. Hajra, and B. T. Tsurutani (2021), Geomagnetically Induced Currents, In: Encyclopedia of Solid Earth Geophysics, Encyclopedia of Earth Sciences Series, 2nd Edition, edited by H. K. Gupta, Springer, Cham., ISBN: 978-3-030-58631-7, https://doi.org/10.1007/978-3-030-58631-7_245.
1. Hajra, R., and B. T. Tsurutani (2018), Magnetospheric “killer” relativistic electron dropouts (REDs) and repopulation: A cyclical process, In: Extreme Events in Geospace: Origins, Predictability, and Consequences, 1st Edition, edited by N. Buzulukova, Elsevier, Netherlands, ISBN: 978-0-12-812700-1, Chapter 14, Pages 373-400, https://doi.org/10.1016/B978-0-12-812700-1.00014-5.
Publications - technical reports
1. Tsurutani, B. T., R. Hajra, E. Echer, W. D. Gonzalez, and O. Santolik (2016), Predicting magnetospheric relativistic > 1 MeV electrons, NASA Tech Briefs (USA), Vol. 40, No. 6, Page 20, NPO-49852, http://assets.techbriefs.com/EML/2016/ntb_digital/NTB0616.pdf & http://www.techbriefs.com/component/content/article/ntb/tech-briefs/software/24815.
Publications - conferences
64. Hajra, R., B. Tsurutani, Q. Lu, G. Lakhina, and A. Du, Ultra-relativistic 7 MeV electron acceleration during intense and long-duration substorm activity, European Geophysical Union (EGU) General Assembly 2024, Vienna, Austria, 14–19 April 2024 (https://meetingorganizer.copernicus.org/EGU24/EGU24-1352.html) (oral by RH). [Highlighted by session conveners as being of public interest]
63. Setsko, P. V., I. V. Despirak, Ya. A. Sakharov, A. A. Lubchich, R. Hajra, G. S. Lakhina, V. N. Selivanov, and B. T. Tsurutani, GIC during strong geomagnetic activity on 23-24 April 2023, 47th Annual Seminar “Physics of Auroral Phenomena”, Polar Geophysical Institute, Apatity, Murmansk region, Russia, 11–15 March 2024 (http://pgia.ru/seminar/admin/?section=1_storm).
62. Hajra, R., and B. T. Tsurutani, High-intensity long-duration continuous auroral electrojet (AE) activity (HILDCAA) events and associated space weather impacts, 7th Asia-Pacific Conference on Plasma Physics, Port-Messe, Nagoya, Japan, 12–17 November 2023 (http://aappsdpp.org/DPP2023/html/3contents/pdf/5479.pdf) (invited talk by RH).
61. Hajra, R., B. T. Tsurutani, E. Echer, Q. Lu, A. Du, and G. S. Lakhina, Ultra-Relativistic Electron Acceleration during High-Intensity Long-Duration Continuous Auroral Electrojet (AE) Activity (HILDCAA) Events, The 15th International Conference on Substorms (ICS-15), Deqing, China, 15–20 October 2023 (http://ics15.cssr.org.cn/OfficeERP_NB/Schedule/ICS-15_booklet_1012.pdf) (oral by RH).
60. Tsurutani, B. T., R. Hajra, G. S. Lakhina, Q. Lu, and B. Ni, A Review of Supersubstorms (SSSs): Their Properties and Their Energetics, The 15th International Conference on Substorms (ICS-15), Deqing, China, 15–20 October 2023 (http://ics15.cssr.org.cn/OfficeERP_NB/Schedule/ICS-15_booklet_1012.pdf) (invited talk of BTT, given by RH).
59. Hajra, R., B. T. Tsurutani, Q. Lu, G. S. Lakhina, A. Du, and L. Shan, Interplanetary shocks between 0.3 and 1.0 au: Helios 1 and 2 observations, The 20th National Symposium on Solar-terrestrial Space Physics, Fuzhou City, Fujian Province, People’s Republic of China, 12–16 April 2023 (https://cssr.scimall.org.cn/meeting/RDKJ/) (oral by RH).
58. Tsurutani, B. T., G. S. Lakhina, R. Hajra, and X. Meng, Magnetic Storm Predictability, Are We Close to Being Able to Do This?, The 5th ISEE Symposium: “Toward the Future of Space–Earth Environmental Research”, Sakata–Hirata Hall, Nagoya University, Higashiyama campus, Nagoya city, Japan, 15–17 November 2022 (https://www.isee.nagoya-u.ac.jp/symposium05/) (solicited talk by BTT).
57. Chen, R., B. T. Tsurutani, X. Gao, Q. Lu, H. Chen, G. S. Lakhina, and R. Hajra, The Structure and Microstructure of Rising-Tone Chorus With Frequencies Crossing at f ~ 0.5 fce, The 5th ISEE Symposium: “Toward the Future of Space–Earth Environmental Research”, Sakata–Hirata Hall, Nagoya University, Higashiyama campus, Nagoya city, Japan, 15–17 November 2022 (https://www.isee.nagoya-u.ac.jp/symposium05/) (poster by RC).
56. Hajra, R., High-Speed Solar Wind Stream Effects on the Topside Ionosphere: High-to-Low Latitude Coupling, National Meet on Aeronomy Research, Theme: Science of Near-Earth Space & Applications, Science Programme Office, ISRO Headquarters, India, 10 May 2022 (https://www.isro.gov.in/one-day-national-meet-aeronomy-research-science-of-near-earth-space-applications) (invited talk by RH).
55. Hajra, R., Supersubstorm (SSS) and Geomagnetically Induced Current (GIC), Planetary Space Weather Workshop, 40th Meeting of the Astronomical Society of India, Indian Institute of Technology Roorkee, India, 25–29 March 2022 (https://www.astron-soc.in/asi2022/sites/default/files/2022-03/ASI_wkshp1.pdf) (invited talk by RH).
54. Sunny, J. V., and R. Hajra, Corotating Interaction Regions during Solar Cycle 24: A Study on Characteristics and Geoeffectiveness, 21st National Space Science Symposium, Indian Institute of Science Education and Research Kolkata, India, 31 January–4 February 2022 (http://www.cessi.in/nsss/Program_Schedule.html) (oral by JVS).
53. Hajra, R., Subauroral Zone Intense Geomagnetically Induced Currents (GICs), Solar wind–Magnetosphere Interaction Workshop, The Johns Hopkins University Applied Physics Laboratory, USA, 30 August–2 September & 13–16 September 2021 (https://secwww.jhuapl.edu/EventLink/Event/32) (invited talk by RH).
52. Hajra, R., The Complex Space Weather Events of September 2017, 2020 URSI Regional Conference on Radio Science (URSI-RCRS 2020), IIT (BHU) Varanasi, India, 12 – 14 February, 2020 (https://conferences.iitbhu.ac.in/URSI-RCRS2020/) (poster by RH).
51. Hajra, R., and B. T. Tsurutani, Intense and long-duration geomagnetically induced current events: solar cycle and geomagnetic dependences, American Geophysical Union (AGU) Fall Meeting, San Francisco, California, USA, 9 – 13 December 2019 (https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/515002) (poster/eLightning presentation by RH).
50. Hajra, R., Importance of Solar Wind High-Speed Streams (HSSs) for Interplanetary Space Weather Study, Recent Advances in Space Science (RASS), Indian Institute of Technology Indore, Indore, Madhya Pradesh, India, 10 – 11 November 2019 (http://rass.iiti.ac.in/speakers.html) (invited talk by RH).
49. Tsurutani, B. T., R. Hajra, T. Tanimori, A. Takada, B. Remya, A. J. Mannucci, G. S. Lakhina, J. U. Kozyra, K. Shiokawa, L. C. Lee, E. Echer, R. V. Reddy, and W. D. Gonzalez, A new mechanism to explain the wilcox et al. (1973) effect, Space Climate 7: The Future of Solar Activity, Canton Orford, Québec, Canada, 8 – 11 July 2019 (http://craq-astro.ca/spaceclimate7/seeabstract.php?id=30#seeabstract) (oral by BTT).
48. Hajra, R., B. T. Tsurutani, and A. K. Patra, Extremely intense substorms/supersubstorms: interplanetary origin and characteristics, AGU Chapman Conference on Scientific Challenges Pertaining to Space Weather Forecasting Including Extremes, Pasadena, California, USA, 11 – 15 February 2019 (https://agu.confex.com/agu/19chapman1/meetingapp.cgi/Paper/473891) (invited talk by RH).
47. Hajra, R., P. Henri, M. Myllys, K. L. Heritier, M. F. Galand, B. T. Tsurutani, and ESA RPC, Impacts of interplanetary corotating interaction regions on cometary plasma: a study by the Rosetta Plasma Consortium, AGU Chapman Conference on Scientific Challenges Pertaining to Space Weather Forecasting Including Extremes, Pasadena, California, USA, 11 – 15 February 2019 (https://agu.confex.com/agu/19chapman1/meetingapp.cgi/Paper/473901) (poster by RH).
46. Tsurutani, B. T., G. S. Lakhina, R. Hajra, R. Bhanu, and A. J. Mannucci, Do we know enough about magnetospheric plasma waves to model where and under what conditions ~10 keV to ~5 MeV magnetospheric electrons will precipitate into the ionosphere?, AGU Chapman Conference on Scientific Challenges Pertaining to Space Weather Forecasting Including Extremes, Pasadena, California, USA, 11 – 15 February 2019 (https://agu.confex.com/agu/19chapman1/meetingapp.cgi/Paper/474596) (invited talk by BTT).
45. Tsurutani, B. T., R. Hajra, T. Tanimori, A.Takada, B. Remya, A.J. Mannucci, G.S. Lakhina, J.U. Kozyra, K. Shiokawa, L.C. Lee, E. Echer, R.V. Reddy, and W.D. Gonzalez, Interplanetary Shock and Heliospheric Plasma Sheet (HPS) Impingements onto the Dayside Magnetosphere and Relativistic ~1 MeV Electron Precipitation (RED) into the Ionosphere: Climate Change?, American Geophysical Union (AGU) Fall Meeting, Washington, D.C., USA, 10 – 14 December 2018 (https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/368891) (invited talk by BTT).
44. Hajra, R., P. Henri, M. Myllys, K. L. Heritier, M. Galand, C. Simon Wedlund, H. Breuillard, E. Behar, N. J. T. Edberg, C. Goetz, H. Nilsson, A. I. Eriksson, R. Goldstein, B. T. Tsurutani, J. More, X. Vallieres, and G. Wattieau, Cometary plasma response to interplanetary corotating interaction regions during 2016 June – September: a quantitative study by the Rosetta Plasma Consortium, European Planetary Science Congress 2018 (EPSC 2018), Berlin, Germany, 16 – 21 September 2018 (https://meetingorganizer.copernicus.org/EPSC2018/EPSC2018-274.pdf) (oral by RH).
43. Wellbrock, A., G. H. Jones, A. J. Coates, C. Simon Wedlund, C. Goetz, N. Dresing, T. A. Nordheim, K. E. Mandt, R. Hajra, M. Myllys, P. Henri, and H. Nilsson, Observations of a Solar Energetic Particle event from inside the comet 67P coma and upstream of the comet, European Planetary Science Congress 2018 (EPSC 2018), Berlin, Germany, 16 – 21 September 2018 (https://meetingorganizer.copernicus.org/EPSC2018/EPSC2018-964.pdf) (oral by AW).
42. Edberg, N. J. T., F. L. Johansson, A. I. Eriksson, C. Simon Wedlund, M. Alho, D. J. Andrews, E. Odelstad, E. Vigren, R. Hajra, and P. Henri, The effect of solar flares on comet 67P and RPC/LAP, European Planetary Science Congress 2018 (EPSC 2018), Berlin, Germany, 16 – 21 September 2018 (https://meetingorganizer.copernicus.org/EPSC2018/EPSC2018-250.pdf) (poster by NJTE).
41. Tsurutani, B. T., R. Hajra, G. S. Lakhina, A. J. Mannucci, and X. Meng, ESA SWARM Assignment: “Magnetic storms and substorms: The role of convection and substorm electrojets, particle precipitation, plasma convection and global current systems during geomagnetic active periods. Focus on recent scientific studies: state of the art, open questions, which are the main achievements and open challenges”, COSPAR 2018, Pasadena, California, USA, 14 – 22 July 2018 (oral by BTT).
40. Tsurutani, B. T., R. Hajra, T. Tanimori, A. Takada, B. Remya, A. J. Mannucci, G. S. Lakhina, J. U. Kozyra, K. Shiokawa, L. C. Lee, E. Echer, R. V. Reddy, and W. D. Gonzalez, Solar/Interplanetary Effects and Possible Consequences for Atmospheric Vorticity, SCOSTEP 14th Quadrennial Solar-Terrestrial Physics Symposium, Toronto, Canada, 9 – 13 July 2018 (http://www.scostepevents.ca/wp-content/uploads/2018/05/Program-Oral-Presentation-Final-1.pdf) (oral by BTT).
39. Hajra, R., P. Henri, M. Myllys, and RPC team, A comparative study on the solar wind impacts on the comet and the Earth, 2nd Young Researcher Conference on Plasma Physics and applications, Sorbonne University, Pierre & Marie Curie Campus, Paris, France, 29 June 2018 (http://www.plasapar.com/en/plas-par-young) (oral by RH).
38. Tsurutani, B. T., G. S. Lakhina, R. Hajra, and A. J. Mannucci, Space Weather Effects in the Magnetosphere, Ionosphere and Thermosphere: What We Know and What Are Current Challenges, Triennial Earth-Sun Summit (TESS), Leesburg, Virginia, USA, 20 – 24 May 2018 (https://agu.confex.com/agu/2018tess/meetingapp.cgi/Paper/334983) (invited talk by BTT).
37. Tsurutani, B. T., R. Hajra, G. S. Lakhina, and A. J. Mannucci, Extreme space weather (ESW) such as the 1859 Carrington magnetic storm: what caused electrical arcing and fires on the ground?, European Geophysical Union (EGU) General Assembly 2018, Vienna, Austria, 8 – 13 April 2018 (http://meetingorganizer.copernicus.org/EGU2018/EGU2018-1892.pdf) (invited talk by BTT).
36. Myllys, M., R. Hajra, P. Henri, M. Galand, K. Héritier, R. Goldstein, N. Edberg, and E. Behar, Impact of co-rotating interaction regions on comet 67P, European Geophysical Union (EGU) General Assembly 2018, Vienna, Austria, 8 – 13 April 2018 (https://meetingorganizer.copernicus.org/EGU2018/EGU2018-13731.pdf) (oral by MM).
35. Breuillard, H., P. Henri, L. Bucciantini, X. Vallieres, A. Eriksson, E. Odelstad, F. Johansson, I. Richter, C. Goetz, J. More, R. Hajra, M. Myllys, G. Wattieaux, and B. T. Tsurutani, Study of plasma waves observed onboard Rosetta in the 67P/ChuryumovGerasimenko comet environment using high time resolution density data inferred from RPC-MIP and RPC-LAP cross-calibration: preliminary results, American Geophysical Union (AGU) Fall Meeting, New Orleans, USA, 11 – 15 December 2017 (poster by BH).
34. Tsurutani, B. T., R. Hajra, T. Tanimori, A. Takada, B. Remya, A. J. Mannucci, G. S. Lakhina, J. U. Kozyra, K. Shiokawa, L. C. Lee, E. Echer, R. V. Reddy, and W. D. Gonzalez, Space Plasma Physics Applied: Global Climate Change, 1st Asia-Pacific Conference on Plasma Physics, Chengdu, China, 18 – 23 September 2017 (http://dpp2017.swip.ac.cn/)/(http://aappsdpp.org/AAPPSDPPF/DPP2017/plenary.html) (invited talk by BTT).
33. Tsurutani, B. T., R. Hajra, G. S. Lakhina, A. J. Mannucci, R. Mcgranaghan, and X. Meng, Magnetic storms and substorms: The role of convection and substorm electrojets, particle precipitation, plasma convection and global current systems during geomagnetic active periods. Focus on recent scientific studies: state of the art, open questions, which are the main achievements and open challenges, Swarm 4D-Ionosphere science meeting, ESA/ESTEC, The Netherlands, 5 – 6 September 2017 (invited talk by BTT).
32. Raizada, S., C. G. M. Brum, B. Fejer, R. Hajra, and E. Echer, F-region response to St. Patrick storm (17-19 March, 2015) over Arecibo, AOGS 14th Annual Meeting, SUNTEC, Singapore, 6 – 11 August 2017 (http://www.meetmatt-svr3.net/aogs/aogs2017/mars2/pubViewAbs.asp?sMode=oral§ionIdO=4&dayRank=5&submit=Browse+Abstracts) (oral by SR).
31. Hajra, R., P. Henri, X. Vallières, N. Gilet, J. Moré, C. Goetz, I. Richter, K. H. Glassmeier, M. F. Galand, K. L. Heritier, A. I. Eriksson, Z. Nemeth, B. T. Tsurutani, M. Rubin, and K. Altwegg, Diamagnetic cavity at comet 67P/Churyumov-Gerasimenko: plasma characteristics and dynamics, European Geophysical Union (EGU) General Assembly 2017, Vienna, Austria, 23 – 28 April 2017 (http://meetingorganizer.copernicus.org/EGU2017/EGU2017-5278.pdf) (oral by RH).
30. Tsurutani, B. T., B. J. Falkowski, C. Goetz, P. Henri, X. Vallieres, R. Hajra, M. Volwerk, K. Altwegg, and K. H. Glassmeier, Large amplitude plasma waves near the comet C-G diamagnetic cavity boundary: what are they and what is the role for cometary plasma dynamics?, European Geophysical Union (EGU) General Assembly 2017, Vienna, Austria, 23 – 28 April 2017 (http://meetingorganizer.copernicus.org/EGU2017/EGU2017-2672.pdf) (oral by BTT).
29. Hajra, R., P. Henri, M. Galand, K. Heritier, N. J. T. Edberg, A. I. Eriksson, J. L. Burch, T. Broiles, R. Goldstein, K. H. Glassmeier, I. Richter, C. Goetz, B. T. Tsurutani, H. Nilsson, K. Altwegg, and M. Rubin, Plasma response to a cometary outburst: Rosetta Plasma Consortium observations during comet 67P/Churyumov-Gerasimenko outburst event on 19 February 2016, American Geophysical Union (AGU) Fall Meeting, San Francisco, California, USA, 12 – 16 December 2016 (http://adsabs.harvard.edu/abs/2016AGUFM.P43A2088H) (poster by RH).
28. Hajra, R., P. Henri, M. Galand, K. Heritier, N. J. T. Edberg, A. I. Eriksson, J. L. Burch, T. Broiles, R. Goldstein, K. H. Glassmeier, I. Richter, C. Goetz, B. T. Tsurutani, H. Nilsson, K. Altwegg, and M. Rubin, Plasma response to a cometary outburst: Rosetta Plasma Consortium observations during comet 67P/Churyumov-Gerasimenko outburst event on 19 February 2016, Comets: A new vision after Rosetta/Philae, Toulouse, France, 14 – 18 November 2016 (http://www.comets2016toulouse.com/) (poster by RH).
27. Tsurutani, B. T., R. Hajra, A. J. Mannucci, E. Echer, F. L. Guarnieri, and W. D. Gonzalez, How to predict relativistic electron acceleration: HILDCAAs, 7th biennial VERSIM and Radiation Belt Symposia (VERSIM-RBS), Hermanus, Western Cape, South Africa, 19 – 24 September 2016 (invited talk by BTT).
26. Tsurutani, B. T., R. Hajra, E. Echer, W. D. Gonzalez, J. W. Gjerloev, Solar wind causes of magnetospheric/magnetotail loading and unloading: extreme ionospheric and atmospheric disturbances (other title: “Extremely Intense (SML ≤ -2500 nT) Supersubstorms (SSS)”), First VarSITI General Symposium (VarSITI2016), Albena, Bulgaria, 06 – 10 June 2016 (http://newserver.stil.bas.bg/VarSITI2016/PDFs/AbstractBookVarSITI2016_low.pdf) (oral by BTT).
25. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez, High-Intensity Long-Duration Continuous AE Activity (HILDCAA) and associated effects on Earth’s outer radiation belt, Space Climate 6, Levi, Finnish Lapland, 04 – 07 April 2016 (http://www.spaceclimate.fi/SC6/absbook.pdf) (invited talk by RH).
24. Tsurutani, B. T., R. Hajra, E. Echer, and J. Gjerloev, Solar and interplanetary causes of extremely intense substorms during superstorms, European Geophysical Union (EGU) General Assembly 2016, Vienna, Austria, 17 – 22 April 2016 (http://meetingorganizer.copernicus.org/EGU2016/EGU2016-1102.pdf) (poster by RH).
23. Tsurutani, B. T., G. S. Lakhina, A. Sen, P. K. Kaw, E. Echer, M. V. Alves, E. Da Costa Jr., R. Hajra, W. D. Gonzalez, J. H. A. Sobral, M. A. Abdu, L. E. Vieira, and C. G. M. Brum, Interplanetary Alfvén waves, HILDCAAs, acceleration of magnetospheric relativistic “killer” electrons and auroral zone heating, 14th International Congress of the Brazilian Geophysical Society (SBGf 2015), Rio de Janeiro, Brazil, 03 – 06 August 2015 (http://m2comunicacoes.com.br/sbgf/trabalhos/trabalhos/sbgf_279.pdf) (oral by BTT).
22. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez, Relativistic electron acceleration during high intensity auroral activities: maximum energy level dependence, European Geophysical Union (EGU) General Assembly 2015, Vienna, Austria, 12 – 17 April 2015 (http://meetingorganizer.copernicus.org/EGU2015/EGU2015-6037.pdf) (poster by BTT).
21. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez, From the Sun to magnetospheric relativistic electrons: a new way to predict the acceleration of relativistic electrons! (Earlier title: “Relativistic (MeV) electron acceleration at geosynchronous orbit during continuous substorm/HILDCAA events”), The 12th International Conference on Substorms (ICS-12), Ise, Japan, 10 – 14 November 2014 (http://www.stelab.nagoya-u.ac.jp/ICS-12/ICS12_program_book.pdf) (oral by RH).
20. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez, Solar cycle dependence and energy coupling during continuous substorm/HILDCAA events, The 12th International Conference on Substorms (ICS-12), Ise, Japan, 10 – 14 November 2014 (http://www.stelab.nagoya-u.ac.jp/ICS-12/ICS12_program_book.pdf) (poster by RH).
19. Tsurutani, B. T., R. Hajra, E. Echer, and P. Newell, The interplanetary causes of supersubstorms (SML < -2000 nT), The 12th International Conference on Substorms (ICS-12), Ise, Japan, 10 – 14 November 2014 (http://www.stelab.nagoya-u.ac.jp/ICS-12/ICS12_program_book.pdf) (poster by BTT).
18. Hajra, R., B. T. Tsurutani, E. Echer, W. D. Gonzalez, and J. W. Gjerloev, Can power outages on Earth be predicted by observations of the Sun?, V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, Natal, Brazil, 29 September – 03 October 2014 (http://www.vsbgea.ccet.ufrn.br/index.php) (oral by RH).
17. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez, High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events and relativistic electron acceleration, V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, Natal, Brazil, 29 September – 03 October 2014 (http://www.vsbgea.ccet.ufrn.br/index.php) (poster by RH).
16. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez, Relativistic (MeV) electron acceleration at geosynchronous orbit during HILDCAA events, X COLAGE: Tenth Latin American Conference on Space Geophysics, Cusco, Peru, 08 – 12 September 2014 (http://jro.igp.gob.pe/x_colage/) (poster by RH).
15. Hajra, R., B. T. Tsurutani, and E. Echer, Relativistic (MeV) electron acceleration at geosynchronous orbit during High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events, Geospace revisited: a Cluster/MAARBLE/Van Allen Probes Conference, Island of Rhodes, Greece, 15 – 20 September 2014 (http://geospacerev.space.noa.gr/images/BookofAbstracts.pdf) (oral by RH).
14. Hajra, R., B. T. Tsurutani, E. Echer, and W. D. Gonzalez, Relativistic E> 0.6,> 2.0 and> 4.0 MeV electron acceleration and HILDCAAs, European Geophysical Union (EGU) General Assembly 2014, Vienna, Austria, 27 April – 02 May 2014 (http://meetingorganizer.copernicus.org/EGU2014/EGU2014-6541.pdf) (poster by BTT).
13. Hajra, R., E. Echer, W. D. Gonzalez, and B. T. Tsurutani, HILDCAAs and associated interplanetary variations: superposed epoch analyses under varying solar activity and seasonal conditions, Parker Workshop on Magnetic Reconnection, Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos, Sao Paulo, Brazil, 18 – 21 March 2014 (poster by RH).
12. Hajra, R., E. Echer, W. D. Gonzalez, and B. T. Tsurutani, Interplanetary dependence of High-Intensity, Long-Duration, Continuous AE Activity (HILDCAA) events, 12o Encontro Brasileiro de Fisica dos Plasmas (EBFP) 2013, Brasilia, Brazil, 01 – 05 December 2013 (oral by RH).
11. Hajra, R., E. Echer, B. T. Tsurutani, and W. D. Gonzalez, Characteristics and energy budget of intense, continuous, auroral electrojet (AE) activity events, 12th Scientific Assembly of International Association of Geomagnetism and Aeronomy (IAGA) 2013, Merida, Yucatan, Mexico, 25 – 31 August 2013 (oral by RH).
10. Hajra, R., E. Echer, W. D. Gonzalez, and B. T. Tsurutani, Morphological features of intense, continuous AE activity events, European Geophysical Union (EGU) General Assembly 2013, Vienna, Austria, 07 – 12 April 2013 (oral by RH).
9. Hajra, R., S. Mazumdar, S. K. Chakraborty, and K. Basu (Roy), A study on the variability of equatorial scintillation around the anomaly crest of the Indian zone, 17th National Space Science Symposium, Sri Venkateswara University, Tirupati, Andhra Pradesh, India, 14 – 17 February 2012 (poster by RH).
8. Hajra, R., S. K. Chakraborty, and A. DasGupta, Ionospheric scintillation activity in relation to ambient ionization near the anomaly crest, National Workshop on Atmospheric and Space Sciences (NWASS-2010), Calcutta, West Bengal, India, 23 – 24 November 2010 (oral by RH).
7. Chakraborty, S. K., R. Hajra, and A. DasGupta, Equatorial scintillation near the anomaly crest in relation to the ambient conditions of the ionosphere, The International Beacon Satellite Symposium (BSS2010), Barcelona, Spain, 07 – 11 June 2010 (poster by SKC).
6. Chakraborty, S. K., and R. Hajra, Variabilities of the ionosphere near the anomaly crest during geomagnetic disturbances, Annual Meeting of Asia and Oceania Geosciences Society (AOGS-2010), Hyderabad International Conference Center, India, 05 – 09 July 2010 (oral by SKC).
5. Chakraborty, S. K., and R. Hajra, Ionosphere near the anomaly crest under geomagnetically disturbed conditions, 16th National Space Science Symposium, Saurashtra University, Rajkot, Gujarat, India, 24 – 27 February 2010 (oral by RH).
4. Chakraborty, S. K., R. Hajra, and A. Paul, Variation of ambient ionization near the crest of the equatorial anomaly in the Indian zone during counter-electrojet events, XV National Space Science Symposium, Radio Astronomy Centre NCRA-TIFR, Udhagamandalam, Ooty, India, 26 – 29 February, 2008 (poster by RH).
3. Chakraborty, S. K., and R. Hajra, A study on variability of ionospheric Total Electron Content during Geomagnetically Disturbed period, Golden Jubilee Symposium of Radio Science (INCURSI-2007), National Physical Laboratory, New Delhi, India, 21 – 24 February 2007 (poster by SKC).
2. Chakraborty, S. K., and R. Hajra, Long term Studies on Variability of Ionospheric Total Electron Content near the Crest of the Equatorial Anomaly in the Indian zone, International Beacon Satellite Symposium-2007, Boston College, USA, 11 – 15 June 2007 (poster by SKC).
1. Chakraborty, S. K., and R. Hajra, Solar control of ambient ionization of the ionosphere near the crest of the equatorial anomaly in the Indian Zone, 2nd UN/NASA Workshop on the International Heliophysical Year and Basic Space Science, Indian Institute of Astrophysics, Bangalore, India, 27 November – 1 December 2006 (poster by SKC).