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

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.

Conjugate Observations of Dayside and Nightside VLF Chorus and QP Emissions Between Arase (ERG) and Kannuslehto, Finland

“…The receiver is composed of two square loop antennas that measure the magnetic field variations in the east-west and north-south directions, respectively. Wave electric and magnetic field spectra are measured by the On-board Frequency Analyzer (OFA) (Matsuda et al, 2018). Further details on the system can be found in Manninen (2005).…”

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.…”

The ERG Science Center

“…The plasma wave experiment (PWE)/waveform capture (WFC) (Kasahara et al 2018b;Matsuda et al 2018) and Software-type wave -particle interaction analyzer (S-WPIA) (Katoh et al 2017;Hikishima et al 2018) have intermittently performed waveform observations along a satellite orbit. Waveform data of plasma waves are important for studying wave-particle interactions through detailed comparisons with the groundbased optical and wave observations (Shiokawa et al 2017).…”