SM21A-2474
Penetration of magnetosonic waves into the plasmasphere observed by the Van Allen Probes
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Fuliang Xiao1, Qinghua Zhou1, Yihua He1, Chang Yang1, Si Liu1, Daniel N. Baker2, Harlan E. Spence3, Geoffrey D Reeves4, Herbert O Funsten5 and J Bernard Blake6, (1)Changsha University of Science and Technology, Changsha, China, (2)University of Colorado at Boulder, Boulder, CO, United States, (3)University of New Hampshire Main Campus, Space Science Center, Durham, NH, United States, (4)Los Alamos National Laboratory, Los Alamos, NM, United States, (5)Los Alamos Natl Laboratory, Los Alamos, NM, United States, (6)Aerospace Corporation Santa Monica, Santa Monica, CA, United States
Abstract:
During the small storm on 14-15 April 2014, Van Allen Probe A measured a continuously distinct proton ring distribution and enhanced magnetosonic (MS) waves along their orbit outside the plasmapause. Inside the plasmasphere, strong MS waves were still present but the distinct proton ring distribution was falling steeply with distance. We adopt a sum of subtracted bi-Maxwellian components to model the observed proton ring distribution and simulate the wave trajectory and growth. MS waves at first propagate towards lower L-shells outside the plasmasphere, with rapidly increasing path gains related to the continuous proton ring distribution. Then they gradually cross the plasmapause into the deep plasmasphere, with almost unchanged path gains due to the falling proton ring distribution and higher ambient density. These results present the first report on how MS waves penetrate into the plasmasphere with aid of the continuous proton ring distributions during weak geomagnetic activities.
