Affiliation:
1. School of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha 410114, China
Abstract
Electron cyclotron harmonic (ECH) waves, contributing significantly to magnetospheric dynamics, usually appear as a series of harmonics between the multiples of electron gyrofrequency. Previous studies have demonstrated that ECH waves are the electron Bernstein mode excited by the electron loss cone distribution. To investigate how the electron distribution controls the frequency and wave normal angle of excited ECH waves, we derive a concise analytic formula for ECH growth rates using the bi-Maxwellian distribution. Parametric studies show that the expansion of the loss cone size could effectively enlarge ECH growth rates and move the peak growth rates to a smaller wave number k (higher frequency) region, while the deepening of the loss cone can only increase the growth rates. It is also found that the growth rate pattern in the k space exhibits different trends on the two sides of 1.5 fce because the dominant resonance orders on the two sides are different. This study further develops our understanding of the generation mechanism of ECH waves.
Funder
National Natural Science Foundation of China
National Natural Science Foundation of Hunan Province
Sicence and Technology Innovation Program of Hunan Province
Foundation of Education Bureau of Hunan Province for Distinguished Young Scientists
Cited by
1 articles.
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