# A reconstruction method of electron density distribution in the equatorial region of magnetosphere

## TL;DR

This paper introduces a new method to estimate electron density in the Earth's magnetosphere's equatorial region using whistler wave measurements, validated with spacecraft data over a decade.

## Contribution

It develops a novel technique for reconstructing electron density from wave field ratios, applicable to existing spacecraft data and enhancing plasma density analysis.

## Key findings

- Successfully applied to Cluster spacecraft data from 2001-2010.
- Can supplement plasma density statistics from recent space missions.
- Useful for reanalyzing wave measurements in the magnetosphere.

## Abstract

A method for the estimation of electron density from the ratio of the wave magnetic and electric field amplitude of whistler waves is developed. Near the geomagnetic equator, whistler wave normals are mainly close to the direction of the background magnetic field. Dispersion relation of whistler wave in the parallel propagation approximation is used in this method. Signals registered by STAFF-SA instrument on board the Cluster spacecraft are used for electron density reconstruction. The Cluster spacecraft crossed the plasmasphere at all local times and in a wide range of latitudes over 10 years (2001-2010) covering well the frequency range of both plasmaspheric hiss and lower band chorus emissions in a vicinity of the geomagnetic equator. The proposed technique can be useful in allowing to supplement plasma density statistics obtained from recent probes (such as THEMIS or Van Allen Probes), as well as for reanalysis of statistics derived from continuous measurements of only one or two components of the wave magnetic and electric fields on board spacecraft covering equatorial regions of the magnetosphere.