TY - JOUR

T1 - Nonlinear development and fourier analysis of the whistler mode instability

AU - Cuperman, S.

AU - Salu, Y.

N1 - Funding Information:
The authors are thankful to Dr W. Bernstein for reading the manuscript, critically, and to Mr T. B. Gray for help in preparing figures 1 (a)-(d). This work was supported in part by NOAA, under contract 1-35120.

PY - 1973/6

Y1 - 1973/6

N2 - The results of the nonlinear computer investigation of the whistler mode instability with the aid of particle-in-cell simulation methods are presented. The electron plasma considered is hot (&?], = 20keV), anisothermal (T1/T1 2t ~ 2) and embedded in a static magnetic field such that ?„ — 0–8. A detailed Fourier analysis of the electromagnetic activity developed under the above stated conditions is carried out: the waves are shown to be electron-like and excellent agreement with the linear stability analysis for the first stages of evolution is found. The feed-back effect of the waves on the particles is shown to result in a continuous decrease of the thermal anisotropy ratio Tinf┴inf/Tinf1inf; corresponding changes in the Fourier spectra of the electromagnetic activity are observed; additional changes in the wave spectrum are introduced by the interaction between various instability modes. At the end of the run (winfpinft ~ 600), the state of the system resembles a quasi-stable equilibrium, in which the electromagnetic energy achieves its maximum value: in this state, unlike the equilibrium one usually considered in the linear stability analysis, a thermally anisotropic plasma withTinf┴inf/Tinf1inf, ~ 1.35 appears to be quasi-stable against the whistler mode instability. This last result is relevant for the geostationary magnetospheric conditions (in the equatorial region) where quasi-stationary states with Tinf┴inf/Tinf1inf about 1–3 are observed.

AB - The results of the nonlinear computer investigation of the whistler mode instability with the aid of particle-in-cell simulation methods are presented. The electron plasma considered is hot (&?], = 20keV), anisothermal (T1/T1 2t ~ 2) and embedded in a static magnetic field such that ?„ — 0–8. A detailed Fourier analysis of the electromagnetic activity developed under the above stated conditions is carried out: the waves are shown to be electron-like and excellent agreement with the linear stability analysis for the first stages of evolution is found. The feed-back effect of the waves on the particles is shown to result in a continuous decrease of the thermal anisotropy ratio Tinf┴inf/Tinf1inf; corresponding changes in the Fourier spectra of the electromagnetic activity are observed; additional changes in the wave spectrum are introduced by the interaction between various instability modes. At the end of the run (winfpinft ~ 600), the state of the system resembles a quasi-stable equilibrium, in which the electromagnetic energy achieves its maximum value: in this state, unlike the equilibrium one usually considered in the linear stability analysis, a thermally anisotropic plasma withTinf┴inf/Tinf1inf, ~ 1.35 appears to be quasi-stable against the whistler mode instability. This last result is relevant for the geostationary magnetospheric conditions (in the equatorial region) where quasi-stationary states with Tinf┴inf/Tinf1inf about 1–3 are observed.

UR - http://www.scopus.com/inward/record.url?scp=84976179247&partnerID=8YFLogxK

U2 - 10.1017/S0022377800007510

DO - 10.1017/S0022377800007510

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AN - SCOPUS:84976179247

VL - 9

SP - 295

EP - 310

JO - Journal of Plasma Physics

JF - Journal of Plasma Physics

SN - 0022-3778

IS - 3

ER -