A5089240058- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Planetary Science and Exploration
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- GNSS positioning and interference
- Spacecraft Design and Technology
- Dust and Plasma Wave Phenomena
- Magnetic Field Sensors Techniques
- Low-power high-performance VLSI design
- Inertial Sensor and Navigation
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Space Satellite Systems and Control
- Embedded Systems Design Techniques
- Advancements in PLL and VCO Technologies
- Spacecraft and Cryogenic Technologies
- Seismic Waves and Analysis
- Atmospheric Ozone and Climate
- Parallel Computing and Optimization Techniques
- Particle accelerators and beam dynamics
- Astrophysics and Cosmic Phenomena
Kyoto University
2016-2025
Kyoto Bunkyo University
1997-2022
United Nations University Institute for Sustainability and Peace
2014-2022
Research Institute for Sustainable Humanosphere
2005-2020
Hitachi (Japan)
1988-2018
Institute of Space and Astronautical Science
2008-2009
Subaru (Japan)
2009
Japan Aerospace Exploration Agency
2008
Japan Science and Technology Agency
2008
Hitachi (United States)
2005
Wave forms of BEN (Broadband Electrostatic Noise) in the geomagnetic tail were first detected by Form Capture receiver on GEOTAIL spacecraft. The results show that most plasma sheet boundary layer (PSBL) are not continuous broadband noise but composed a series solitary pulses having special form which we term “Electrostatic Solitary Waves (ESW)”. A nonlinear BGK potential model is proposed as generation mechanism for ESW based upon simple particle simulation considers highly evolution...
The Exploration of energization and Radiation in Geospace (ERG) project explores the acceleration, transport, loss relativistic electrons radiation belts dynamics for geospace storms. This consists three research teams satellite observation, ground-based network integrated data analysis/simulation. synergetic approach is essential obtaining a comprehensive understanding electron generation/loss processes as well storms through cross-energy/cross-regional couplings, which different...
The Exploration of energization and Radiation in Geospace (ERG) project aims to study acceleration loss mechanisms relativistic electrons around the Earth. Arase satellite was launched on December 20, 2016, explore heart Earth's radiation belt. In present paper, we introduce specifications Plasma Wave Experiment (PWE) board satellite. inner magnetosphere, plasma waves, such as whistler-mode chorus, electromagnetic ion cyclotron wave, magnetosonic are expected interact with particles over a...
We present computer experiments of electrostatic solitary waves (ESW) observed by Geotail in the magnetotail. ESW correspond to broadband noise, and they are excited through electron two‐stream instabilities along a static magnetic field. performed one‐dimensional particle simulations involving two beams an ion beam traveling vary density ratio thermal velocities beams. The values these parameters strongly affect diffusion processes beams, accordingly, different types generated. studied four...
The High Frequency Analyzer (HFA) is a subsystem of the Plasma Wave Experiment onboard Arase (ERG) spacecraft. main purposes HFA include (1) determining electron number density around spacecraft from observations upper hybrid resonance (UHR) waves, (2) measuring electromagnetic field component whistler-mode chorus in frequency range above 20 kHz, and (3) observing radio plasma waves excited storm-time magnetosphere. Two components AC electric fields detected by Wire Probe Antenna one...
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well their interactions with the solar wind, radiation, interplanetary dust. Many scientific instruments onboard spacecraft be completely, or partially devoted study near-space environment of complex processes that govern it. issues remain unsolved even after MESSENGER ended in 2015. specific...
We developed the onboard processing software for Plasma Wave Experiment (PWE) 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), High-Frequency Analyzer. designed a pseudo-parallel scheme with time-sharing system achieved simultaneous signal each receiver. Since electric magnetic field signals are processed by different CPUs, we synchronized observation...
We present simulations of the electrostatic solitary waves (ESW) as observed by GEOTAIL which have been identified broadband noise (BEN) in previous studies. found that ESW are generated a result nonlinear coalescence strong excited an beam instability. This instability is driven electron drifting relative to ions and other electrons with ions. As necessary condition for generation ESW, ion thermal velocity must be large enough so prevent decay acoustic waves. Another density larger than 30%...
The main scientific objectives of GEOTAIL Plasma Wave Instrument (PWI) are to investigate the characteristic features wave phenomena which generated by a variety plasma processes occurring within Earth's magnetosphere. PWI measures waves in frequency range from 5.62 Hz 800 kHz for electric components and 12.5 magnetic components. instrument is composed three distinct sets receivers: (1) Sweep Frequency Analyzer (SFA), (2) Multi-Channel (MCA) (3) Wave-Form Capture (WFC). first two receivers...
When a Coronal Mass Ejection struck the Earth on January 10, 1997, Electrostatic Solitary Waves (ESW) and Amplitude Modulated (AMEW) were detected as GEOTAIL skimmed along dayside magnetopause observed 3‐dimensional multiple x‐line magnetic reconnection. The ESW had amplitudes up to ∼20mV/m evolved from two‐dimensional structures with smaller one‐dimensional larger amplitudes. observation of AMEW show that enhanced broadband electrostatic emissions associated reconnection are not random...
Power consumption analyzes of embedded processors indicate that a significant amount power is consumed in accessing memory and the control path. Based on this, runtime characteristics signal processing applications, we advocate use instruction buffering as power-saving technique for multimedia applications. Two approaches, decoded buffer (DIB) cache, are considered. Performance improvements representative applications speech such as, vector sum excited linear prediction (VSELP), coding...
On 11 December 1994 the Geotail spacecraft encountered an active reconnection diffusion region around X line in Earth's magnetotail. Three interesting features were observed. One is quadrupole pattern of out‐of‐plane B y magnetic field component during passage islands and crossing neutral sheet. The second a direction reversal electron beams vicinity separatrix topology reconnection. third clear plasma flow reversal. By combining observations plasma, field, particles, waves, this report may...
This paper summarizes the specifications and initial evaluation results of Wire Probe Antenna (WPT) Electric Field Detector (EFD), key components for electric field measurement Plasma Wave Experiment (PWE) aboard Arase (ERG) satellite. WPT consists two pairs dipole antennas with ~ 31-m tip-to-tip length. Each antenna element has a spherical probe (60 mm diameter) at each end wire (15 m length). They are extended orthogonally in spin plane spacecraft, which is roughly perpendicular to Sun...
Broadband electrostatic noise (BEN) and narrowband (NEN) are common wave activities in the plasma sheet boundary tail lobe regions, respectively. Similar emissions can be observed magnetosheath region. We demonstrate nature of these waves based on waveform observations by instrument board Geotail spacecraft. The above waveforms divided into two types classifications. BEN type consist a series isolated bipolar pulses. They termed after their as layer solitary (PSBL ESW) (MS ESW). On other...
The ‘whistler critical Mach number’, M crit w , is one of the dimensionless parameters that characterizes collisionless shocks. Originally, it was introduced to indicate point above which whistler waves do not propagate upstream. Indeed our analysis Geotail data at Earth's bow shock shows intense in sub‐critical regime, A < but super‐critical regime. In this paper, we further report seems regulate electron acceleration efficiency At transition layer found spectral index Γ energy spectra...
Magnetospheric substorms are among the most dynamic phenomena in Earth&#8217;s magnetosphere, yet their triggering mechanisms remain unclear. Ground-based observations have identified auroral beads as precursors to substorms. Here, we report a new precursor feature space-based kilometric radiation (AKR), marked by appearance of emissions with slowly frequency-drifting tones (
<title>Abstract</title> The SS-520-3 sounding rocket was launched on November 4th, 2021 as part of the Grand Challenge Initiative - Cusp from Ny-Ålesund, Svalbard. into cusp ionosphere during main phase a geomagnetic storm. In this study we utilize two low energy particle analyzers well multi-needle Langmuir probe and an impedance payload. This aims to provide overview flight conditions range ground-based instruments scintillation receivers. We were able confirm that entered through poleward...
Abstract Whistler‐mode chorus waves play important roles in the development of energetic electron populations Earth's inner magnetosphere. We have statistically analyzed rapid changes flux associated with using data from Arase satellite. The satellite observations obtained 23 March 2017 to 12 October 2018 show that are concentrated near magnetic equator nightside dawnside. compared energy and pitch angle range region bounded by resonance curve whistler mode which calculated properties...
We performed computer simulations of electrostatic solitary waves (ESW), which correspond to broadband noise (BEN), observed by Geotail spacecraft in the magnetotail. According Geotail/WFC data analysis, ESW are composed sequences impulsive waves, and their potentials revealed have uniform structures direction perpendicular ambient magnetic field. a series two‐dimensional particle with cold electron beam drifting against background hot electrons along In these simulations, spatial excited...
Lion roars in the magnetosheath are studied based on waveform data recorded by Geotail plasma wave instrument (PWI). It is found that about 30% (type A) of lion associated with mirror waves or decrease ambient magnetic field ( B 0 ). About 70% B) not . Both types cover a frequency range from 0.02Ω e to 0.75Ω However, dominant frequencies around 0.12Ω , where Ω electron cyclotron frequency. The amplitudes few picoteslas hundreds picoteslas. Their average amplitude 110 pT. Most these propagate...