SM41A-4224:
First Simultaneous Observations of Lower Hybrid, Whistler Mode, Electrostatic Solitary, and Electron Cyclotron Waves Near the Earth's Magnetopause
Thursday, 18 December 2014
Xiangwei Tang1, Cynthia A Cattell1, Lynn B Wilson III2 and Robert J Alexander3, (1)University of Minnesota, School of Physics and Astronomy, Minneapolis, MN, United States, (2)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (3)Organization Not Listed, Washington, DC, United States
Abstract:
Wave modes including lower hybrid waves (LHW), whistler mode waves (WW), electrostatic solitary waves (ESW) and electron cyclotron waves (ECW) have been frequently observed in the Earth’s magnetosphere and at the Earth’s magnetopause. We present the first simultaneous observations of these waves at the low latitude boundary layer (LLBL) of the Earth's magnetopause using data from the THEMIS-E satellite. The waves were identified through auditory analysis in the high resolution (16384 samples/s) electric field burst data and occurred at the same time as large fluctuations of plasma density and temperature (at time scales of ~3 to 4 minutes) at a location of 9.3 Re, 14.4 magnetic local time, and 5.8 degrees magnetic latitude. Large fluctuations in the interplanetary magnetic field and solar wind flow speed were observed associated with this wave event and could be responsible for the variations seen in the LLBL at THEMIS-E. The particle distribution functions show that lower-energy ions (<1.3 KeV) are anisotropic with Ti_perp > Ti_para while lower-energy (<300 eV) electrons are anisotropic with Te_perp < Te_para. In addition, electrons show a double-peaked distribution, i.e., bi-streaming beams. These distributions are consistent with instability mechanisms proposed for the observed waves. The results provide insights into wave coupling near the magnetopause and suggest that coupling processes may be more important than previously thought.
