Estimation of the Electron Density in the Near 3–4 RE Magnetosphere Based on the Measurement of the Interball-2 Satellite Potential

Abstract

A new method is proposed for determining the electron density in rarefied plasma, based on simultaneous measurements of the Interball-2 satellite potential using IESP-2 (electric field instrument) and KM-7 (electron temperature sensor) probe devices. This makes it possible to estimate the photoelectron current density based on a procedure proposed earlier by the authors of this study. The electron concentration was determined only for the positive potential of the spacecraft. The balance equations for the satellite and the probe between the currents of the surrounding plasma electrons and photoelectrons emitted by the illuminated surface were compiled. In the magnetosphere, to bring the probe potential to the potential of the surrounding plasma, a bias current is directed into the probe, which was taken into account in the current balance equation for the probe. The electron energy used in the calculations was kTe = 1 eV. We analyzed data from ~350 orbits in the auroral region of the magnetosphere at altitudes of 2–3 RE from October 1996 to March 1998 during the period of low solar activity at the beginning of the 23rd cycle. Examples of the calculated electron density are given, which is in the range of 1–30 cm–3.