Effect of upflowing field-aligned electron beams on the electron cyclotron waves in the auroral magnetosphere

Abstract

The role of low density upflowing field-aligned electron beams (FEBs) on the growth rate of the electron cyclotron waves at the frequencies ωr < Ωe, propagating downward in the direction of the Earth's magnetic field, has been analysed in the auroral region at ωe/Ωe < 1 where ωe is the plasma frequency and Ωe is the gyrofrequency. The FEBs with low to high energy (E b ) but with low temperature (T b ) have no effect on these waves. The FEBs with E b < 1 keV and T b (>1.5 keV) have been found to have significant effect on the growth rate. Analysis has revealed that it is mainly the T b which inhibits the growth rate (magnitude) and the range of frequency (bandwidth) of the instability mainly in the higher frequency spectrum. The inhibition in the growth rate and bandwidth increases with increase in T b . The FEBs with less E b (giving drift velocity) reduce growth rate more than the beams with larger E b . The inhibition of growth rate increases with the increase in the ratio ωe/Ωe indicating that the beams are more effective at higher altitudes.

Electromagnetic Electron-Cyclotron Wave for Ring Distribution with Alternating Current (AC) Electric Field in Saturn Magnetosphere

“…The distribution function of trapped electrons can be described as Maxwellian ring, as Wu et al (1989) and Kumar et al (2007) http://janss.kr…”

Effect of the Relativistic Electron Beam on Propagating Whistler-Mode Wave for Ring Distribution in the Saturn Magnetosphere

“…Whistler's launch mode is also activated when it is created by lightning. The addition of relativistic energetic hot electrons in bulk alters the growth rate by raising its maximum value [3]. A crucial mechanism that might result in wave amplification and the precipitation of high-energy electrons as from magnetic region into the lower atmosphere is the interaction of Whistler mode wave particles.…”