Excitation of Whistler-Mode (Chorus) Emissions during Terrestrial Substorms
XIAO Fu-Liang1,2, ZHAO Hua1, HE Hui-Yong2
1Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080
2Department of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410076
Excitation of Whistler-Mode (Chorus) Emissions during Terrestrial Substorms
XIAO Fu-Liang1,2;ZHAO Hua1;HE Hui-Yong2
1Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080
2Department of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410076
Abstract： The enhanced growth rate of whistler mode waves has been evaluated during an injection event associated with an isolated terrestrial substorm that occurred at 23:00 UT, on January 21, 1991. The electron phase space density observed by an LEPA instrument on the board of the CRRES spacecraft is modelled by using a bi-loss-cone distribution function (composed of a high anisotropic component and a quasi-isotropic component). During the injection event, the path integrated gain may increase by a factor of 5 over a frequency range near a few tenths of the electron gyrofrequency, which is consistent with the enhancement observed in the CRRES plasma wave experiment (PWE) emissions. Scattering of electrons by the enhanced whistler mode waves causes the pitch angle distribution of resonant electrons to a quasi isotropic (flat-top) distribution during the terrestrial substorm injection event.
2005, Vol. 22 
