Evaluation of the calibrated waveform data observed by the plasma wave experiment on board the Arase satellite

The Arase satellite was launched in December 2016 for the purpose of understanding wave-particle interaction process in the inner magnetosphere. PWE(Plasma Wave experiment) on board Arase measures the electric and magnetic field components of plasma waves. In particular, WFC, which is one of the PWE receivers, measures waveform of two electric field components from DC to 20 kHz and three magnetic field components from a few Hz to 20 kHz with a sampling rate of 65 kHz.

Waveform data obtained by WFC should be calibrated by the end-to-end frequency response of the WFC receiver including the preamplifier. In particular, the antenna impedance of the electric field sensor changes dynamically depending on the plasma environment around the satellite. In order to achieve accurate electric field measurement, it is important to evaluate the effect of the antenna impedance as well as the frequency response of the receiver.

In this study, we compare the refractive index calculated from the calibrated waveform data for several chorus events with the theoretical values obtained by the Appleton-Hartree's equation. We discuss the accuracy of the calibrated electromagnetic field waveform under the several conditions of antenna impedance to improve waveform calibration.