SM41E-2522
Storm-time occurrence and Spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes Statistical study
Thursday, 17 December 2015
Poster Hall (Moscone South)
Lei Dai1, Kazue Takahashi2, Robert L Lysak3, Chi Wang4, John R Wygant5, Craig Kletzing6, John W Bonnell7, Cynthia A Cattell5, Charles William Smith8, Robert J. MacDowall9, Scott A Thaller5, Aaron W Breneman10, Xiangwei Tang5, Xin Tao11 and Lunjin Chen12, (1)Center for Space Science and Applied Research (CSSAR), CAS, Beijing, China, (2)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (3)University of Minnesota Twin Cities, School of Physics and Astronomy, Minneapolis, MN, United States, (4)CSSAR, CAS, Beijing, China, (5)University of Minnesota Twin Cities, Minneapolis, MN, United States, (6)University of Iowa, Iowa City, IA, United States, (7)University of California Berkeley, Berkeley, CA, United States, (8)University of New Hampshire Main Campus, Durham, NH, United States, (9)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (10)The University of Minnesota, Minneapolis, MN, United States, (11)University of Science and Technology of China, Hefei, China, (12)University of Texas at Dallas, Richardson, TX, United States
Abstract:
Poloidal ULF waves are capable of interacting with energetic particles in the ring current and the radiation belt. The statistical properties of the waves are important for evaluating their impact on energetic particles during storms. Using Van Allen Probes (RBSP) data during ~10 storms from October 2012 to July 2014, we investigate the spatial distribution and storm-time occurrence of Pc4 (7-25 mHz) poloidal waves in the inner magnetosphere. Pc4 poloidal waves are sorted into two categories: waves with and without significant magnetic compressional components. Major statistic results from these 10 storms are: 1) Both types of poloidal waves have much higher occurrence rate during storms. 2) The non-compressional (guided) poloidal waves mostly occurred in the late recovery phase, suggesting an internal wave source related to the decay of the ring current. 3) The dayside compressional Pc4 poloidal waves are strongly correlated with the storm-time variations of the solar wind dynamic pressure, indicating their external wave source in the solar wind. 4) Both compressional and non-compressional waves preferentially occur on the dayside near noon at L~5-6. The RBSP statistical results may shed light on the storm-time generation, propagation of poloidal ULF waves, as well as their impact on the ring current and radiation belt particles.
