A new whistler inversion method

Abstract

A new whistler inversion method has been developed to obtain plasmaspheric electron densities and propagation paths deduced from measured whistler data. It is based on the exact Appleton-Hartree dispersion relation and recent experimental density distribution models, comprising the following components: a longitudinal whistler wave propagation model; an empirical electron density distributions model along the field lines based on Polar spacecraft data; and dipole and International Geomagnetic Reference Field approximation of the Earths magnetic field. The new method predicts electron densities and propagation paths different from the earlier methods. The validation of the method is difficult owing to lack of in situ measurements. A multiple-path whistler group model was introduced in addition to the whistler inversion method assuming a simplified (logarithmic) dependence of equatorial electron density. A new, time-frequency domain transformation of multiple path groups led us to validate the components of the whistler inversion method, and it adds a major extension to the inversion method in the case of multiple-path whistler groups. Beside that, the method is capable of providing electron density profiles for the plasmasphere by the analysis of multiple-path propagation whistlers. Copyright 2009 by the American Geophysical Union.