Effect of a parallel electric field on the whistler mode instability in the magnetosphere

Abstract

A dispersion relation for the whistler mode wave propagation in an anisotropic warm magnetoplasma in the presence of a weak parallel electrostatic field has been derived from linearized coupled Boltzmann‐Maxwell equations with collision frequency independent of particle velocity. An expression for the growth rate has been derived in the presence of an electric field and for small temperature anisotropy (A<1) for the whistler mode wave. Under suitable approximation we recover the earlier known results. The modifications introduced in the growth rate by the electric field and temperature anisotropy have been discussed using observed plasma parameters at 6.6 RE. It is observed that growth (damping) of whistler mode waves is possible when the wave vector is parallel (antiparallel) to the static electric field. The effect of the electric field is more pronounced at low frequency (higher wave number) wave spectrum.

Effect of parallel electric fields on whistler mode waves in an anisotropic Jovian magnetospheric plasma

“…The applied electric field parallel to the magnetic field has the effect of modifying the thermal electron velocity in that direction which is equivalent to saying that the temperature Tll in the direction of magnetic field modifies to the complex temperature qlC as Tic = ql(l -je&lkK~l> , (2) where k is the wave number and e is the charge of electrons. The dispersion relation is expressed as (Misra et al, 1979) where…”

“…The growth rate of the whistler mode instability in an anisotropic Jovian magnetospheric plasma for different parameters at L = 5.6 Rj has been computed with the help of general dispersion relation for the whistler mode wave for a drifted bi-Maxwellian distribution function (Misra et al, 1979).…”

Study of Electromagnetic Ion-Cyclotron Instability in a Magnetoplasma

“…Contribution of A.C. frequency reduces the upper limit of wave number k and normalized real frequency X 3 = ω r /ω ci and increases the growth rate. The A.C. frequency appears only through modification of resonant instability [32,41]. Figure 2 shows the temporal growth rate with proton temperature ratio of 1.5 to 2.5 for an an-isotropic bi-Maxwellian and loss cone plasma.…”

Excitation of oblique whistler waves in magnetosphere and in interplanetary space at 1 A.U.

“…Plasma waves in the vicinity of the magnetopause at ELF/VLF frequencies propagating waves have been studied by many researchers (Rycroft, 1972;Singh, 1977, 1980;Misra et al, 1979;LaBelle and Treuman, 1988;Sazhin, 1988Sazhin, , 1993Tsurutani, 1981Tsurutani, , 1989Misra and Haile, 1993;Misra and Pandey, 1995). Intensification of these waves are general features of magnetopause crossings.…”