Can magnetospheric electron temperature be inferred from whistler dispersion measurements?
Abstract
An approximate expression for whistlermode group velocity is obtained, taking into account the effects of electron temperature and anisotropy, density and ion effects, effects of oblique propagation and a nondipolarity of the dayside magnetospheric magnetic field. This expression is applied to the propagation of whistlers between one hemisphere and the other. It is pointed out that at frequencies close to the upper cutoff of whistler spectra, perturbations to whistler group delay times due to temperature effects can be of the same order of magnitude as, or even higher than, the corresponding perturbations due to finite electron density and ion effects. A method of magnetospheric electron temperature diagnostics is proposed and applied to two whistlers recorded at Halley (L = 4.3). It is pointed out that the values of temperature obtained from the analysis of whistler spectra depend on the choice of model of electron density and temperature distribution in the magnetosphere and on the effect of ducted ray path on whistler delay times which is difficult to take into account in the computations.
 Publication:

Annales Geophysicae
 Pub Date:
 April 1990
 Bibcode:
 1990AnGeo...8..273S
 Keywords:

 Earth Magnetosphere;
 Electromagnetic Interference;
 Electron Energy;
 Magnetospheric Electron Density;
 Whistlers;
 Ionospheric Electron Density;
 Lightning;
 Magnetic Field Configurations;
 Perturbation Theory