Control of southward interplanetary magnetic field within high-speed streams on whistler mode waves in the inner magnetosphere (Invited)
Friday, 5 September 2014: 2:40 PM
Regency Ballroom (Hyatt Regency)
Yoshizumi Miyoshi, Nagoya Univ, Nagoya, Aichi, Japan, Ryuho Kataoka, National Institute of Polar Research, Tachikawa, Japan, Yoshiya Kasahara, Kanazawa University, Kanazawa Ishikawa, Japan, Tsugunobu Nagai, Tokyo Inst Tech I2-5, Tokyo, Japan, Atsushi Kumamoto, Tohoku Univ, Sendai, Japan, Michelle F Thomsen, Planetary Science Institute, Los Alamos, NM, United States and Vania Jordanova, Los Alamos National Laboratory, Los Alamos, NM, United States
Abstract:
Using the long-term, for more than one solar cycle, data from Akebono satellite, we demonstrate that during HSS events with the southward interplanetary magnetic field (IMF)-dominant HSS (SBz-HSS), whistler mode chorus waves are enhanced, while during HSS events with the northward IMF-dominant HSS, the wave activity is very weak. We also investigate several parameters associated with the whistler mode wave-electron interactions. During SBz-HSS events, hot electron injections occur and the thermal plasma density decreases due to the shrinkage of the plasmapause, causing large flux enhancement of relativistic electrons through whistler-mode wave excitation. In fact, the large flux enhancement of the outer belt is seen in the SBz-HSS events, while the flux enhancement is weak in the NBz-HSS events. A series of substorms are essential to produce continuous activity of whistler waves because of continuous hot electron injections from the plasma sheet. These results explain why large flux enhancement of relativistic electrons tends to occur during SBz-HSS events and show the importance of whistler mode wave-electron interactions. We also show the RAM-simulation results to calculate whistler mode waves for SBz-HSS events and NBz-HSS events and compare with the observations.
