Onboard software of Plasma Wave Experiment aboard Arase: instrument management and signal processing of Waveform Capture/Onboard Frequency Analyzer

Shoya Matsuda,Mamoru Ota,Satoshi Yagitani,Yasumasa Kasaba,Yoshizumi Miyoshi,Tomohiko Imachi,Atsushi Kumamoto,Hirotsugu Kojima,Satoshi Kurita,Iku Shinohara,Yoshiya Kasahara,Fuminori Tsuchiya,Mitsuru Hikishima,Mitsunori Ozaki,Keigo Ishisaka,Ayako Matsuoka

doi:10.1186/s40623-018-0838-0

Abstract

We developed the onboard processing software for the Plasma Wave Experiment (PWE) onboard the Exploration of energization and Radiation in Geospace, Arase satellite. The PWE instrument has three receivers: Electric Field Detector, Waveform Capture/Onboard Frequency Analyzer (WFC/OFA), and the High-Frequency Analyzer. We designed a pseudo-parallel processing scheme with a time-sharing system and achieved simultaneous signal processing for each receiver. Since electric and magnetic field signals are processed by the different CPUs, we developed a synchronized observation system by using shared packets on the mission network. The OFA continuously measures the power spectra, spectral matrices, and complex spectra. The OFA obtains not only the entire ELF/VLF plasma waves’ activity but also the detailed properties (e.g., propagation direction and polarization) of the observed plasma waves. We performed simultaneous observation of electric and magnetic field data and successfully obtained clear wave properties of whistler-mode chorus waves using these data. In order to measure raw waveforms, we developed two modes for the WFC, ‘chorus burst mode’ (65,536 samples/s) and ‘EMIC burst mode’ (1024 samples/s), for the purpose of the measurement of the whistler-mode chorus waves (typically in a frequency range from several hundred Hz to several kHz) and the EMIC waves (typically in a frequency range from a few Hz to several hundred Hz), respectively. We successfully obtained the waveforms of electric and magnetic fields of whistler-mode chorus waves and ion cyclotron mode waves along the Arase’s orbit. We also designed the software-type wave–particle interaction analyzer mode. In this mode, we measure electric and magnetic field waveforms continuously and transfer them to the mission data recorder onboard the Arase satellite. We also installed an onboard signal calibration function (onboard SoftWare CALibration; SWCAL). We performed onboard electric circuit diagnostics and antenna impedance measurement of the wire-probe antennas along the orbit. We utilize the results obtained using the SWCAL function when we calibrate the spectra and waveforms obtained by the PWE.

Highlights

Recent observations and simulation studies suggest that the whistler-mode chorus wave has an important role in the internal acceleration of radiation belt electrons (Foster et al 2017; Katoh and Omura 2007; Reeves et al 2013; Li et al 2014)
We will focus on the measurement of the electric field evolution and the natural plasma wave related to the inner magnetospheric dynamics
S‐WPIA mode When the Plasma Wave Experiment (PWE) instrument receives a request for software-type wave–particle interaction analyzer (S-WPIA) data generation from the mission data recorder (MDR), the WFC continuously generates and stores 5 components of the electric and magnetic field waveforms to the MDR

Summary

Introduction

Recent observations and simulation studies suggest that the whistler-mode chorus wave has an important role in the internal acceleration of radiation belt electrons (Foster et al 2017; Katoh and Omura 2007; Reeves et al 2013; Li et al 2014). The Plasma Wave Experiment (PWE) is one of the scientific instruments onboard the Arase satellite and is used to measure the electric field and magnetic field in the inner magnetosphere (Kasahara et al 2018). Continuous observation of low-frequency electric field waveform (for the measurement of EMIC waves).

Results

Conclusion