Magnetic Search Coil (MSC) of Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite

Abstract

This paper presents detailed performance values of the Magnetic Search Coil (MSC) that is part of the Plasma Wave Experiment on board the Arase (ERG) satellite. The MSC consists of a three-axis search coil magnetometer with a 200-mm-long magnetic core. The MSC plays a central role in the magnetic field observations, particularly for whistler mode chorus and hiss waves in a few kHz frequency range, which may cause local acceleration and/or rapid loss of radiation belt electrons. Accordingly, the MSC was carefully designed and developed to operate well in harsh radiation environments. To ascertain the wave-normal vectors, polarizations, and refractive indices of the plasma waves in a wide frequency band, the output signals detected by the MSC are fed into the two different wave receivers: one is the WaveForm Capture/Onboard Frequency Analyzer for waveform and spectrum observations in the frequency range from a few Hz up to 20 kHz, and the other is the High Frequency Analyzer for spectrum observations in the frequency range from 10 to 100 kHz. The noise equivalent magnetic induction of the MSC is 20 fT/Hz 1/2 at a frequency of 2 kHz, and the null depth of directionality is − 40 dB, which is equivalent to an angular error less than 1 •. The MSC on board the Arase satellite is the first experiment using a current-sensitive preamplifier for probing the plasma waves in the radiation belts.

Microscopic Observations of Pulsating Aurora Associated With Chorus Element Structures: Coordinated Arase Satellite‐PWING Observations

“…The coordinated observations by the Arase satellite and the ground-based PWING observation network have allowed more complete study of the origin of intensity modulations less than 1 s in pulsating auroras, which has been an open issue in auroral physics since the 1970s (Royrvik & Davis, 1977). Matsuda et al, 2018;Ozaki et al, 2018) and for aurora at 1/100 s (Shiokawa et al, 2017); see Texts S1 and S2 in the supporting information. Our sampling is for waves at 1/65,536 s (Y.…”

“…Our sampling is for waves at 1/65,536 s (Y. Matsuda et al, 2018;Ozaki et al, 2018) and for aurora at 1/100 s (Shiokawa et al, 2017); see Texts S1 and S2 in the supporting information. Figure 1 shows a notable conjugate event between Arase and the Gakona ground station (62.39°N, 214.78°E, L = 5.1, one of multiple ground sites in the PWING network), observed in the late recovery phase (Dst = À22 nT) of a magnetic storm, at 13:13 UT, 30 March 2017.…”

Electrostatic Electron Cyclotron Harmonic Waves as a Candidate to Cause Pulsating Auroras

“…We utilized the Onboard Frequency Analyzer (OFA; Matsuda et al, ), which is one of the receivers of the Plasma Wave Experiment (Y. Kasahara, Kasaba, et al, ) onboard the Arase satellite. The OFA processes signals from two pairs of dipole wire‐probe antennas (Kasaba et al, ) and tri‐axis magnetic search coils (Ozaki et al, ) and produces a single‐channel power spectrum for the electric and magnetic field (OFA‐SPEC), covering the frequency range from 64 Hz to 20 kHz. The number of frequency points depends on the operation mode of the OFA.…”

Deformation of Electron Pitch Angle Distributions Caused by Upper Band Chorus Observed by the Arase Satellite

“…PWE consists of triaxial magnetic search coil (Ozaki et al, ), two pairs of wire probe antennas (WPT; Kasaba et al, ), and receivers which cover three different frequency ranges. Signals from magnetic search coil and WPT in the frequency range from a few Hz to 20 kHz are processed by Onboard Frequency Analyzer (OFA; Matsuda et al, ) and OFA computes spectral power density as well as spectral matrices of electromagnetic fields.…”