Shoichiro Yokota
A5034252221- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Planetary Science and Exploration
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Space Exploration and Technology
- Magnetic confinement fusion research
- Space Science and Extraterrestrial Life
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Atmospheric Ozone and Climate
- Spacecraft and Cryogenic Technologies
- Spacecraft Design and Technology
- Space Satellite Systems and Control
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Mass Spectrometry Techniques and Applications
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Atomic and Subatomic Physics Research
- Spacecraft Dynamics and Control
- Space exploration and regulation
Osaka University
2017-2025
Osaka Health Science University
2018-2025
Toneyama National Hospital
2017-2024
Morinomiya University of Medical Sciences
2024
Kyoto University
2024
The University of Tokyo
2024
Kyushu Institute of Technology
2024
Tohoku University
2022
Graduate School USA
2018-2019
John Wiley & Sons (United States)
2016-2018
The Fast Plasma Investigation (FPI) was developed for flight on the Magnetospheric Multiscale (MMS) mission to measure differential directional flux of magnetospheric electrons and ions with unprecedented time resolution resolve kinetic-scale plasma dynamics. This increased has been accomplished by placing four dual 180-degree top hat spectrometers around periphery each MMS spacecraft. Using electrostatic field-of-view deflection, eight species together provide 4pi-sr with, at worst,...
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) Science Center serves as a hub the ERG project, providing data files common format developing space physics environment analysis software plug-ins for analysis. also develops observation plans (Arase) satellite according to science strategy project. Conjugate observations with other satellites ground-based are planned. These tasks contribute project by achieving quick well-organized conjugate observations.
Abstract Martian moons exploration, MMX, is the new sample return mission planned by Japan Aerospace Exploration Agency (JAXA) targeting two with scheduled launch in 2024 and to Earth 2029. The major scientific objectives of this are determine origin Phobos Deimos, elucidate early Solar System evolution terms volatile delivery across snow line terrestrial planets having habitable surface environments, explore evolutionary processes both Mars environment. To achieve these objectives, during a...
Interaction between the solar wind and objects in system varies largely according to settings, such as existence of a global intrinsic magnetic field and/or thick atmosphere. The Moon's case is characterized by absence both them. Low energy ion measurements on lunar orbit realized more than 30 years after Apollo period low charged particle analyzers MAP‐PACE board SELENE(KAGUYA). sensors have found that 0.1%∼1% protons are reflected back from Moon instead being absorbed surface. Some ions...
The medium-energy particle experiments—electron analyzer onboard the exploration of energization and radiation in geospace spacecraft measures energy direction each incoming electron range 7–87 keV. sensor covers a 2π-radian disklike field view with 16 detectors, full solid angle coverage is achieved through spacecraft’s spin motion. independently measured by both an electrostatic avalanche photodiodes, enabling significant background reduction. We describe technical approach, data output,...
Abstract Based on high‐resolution measurements from NASA's Magnetospheric Multiscale mission, we present the dynamics of electrons associated with current systems observed near diffusion region magnetic reconnection at Earth's magnetopause. Using pitch angle distributions (PAD) and curvature analysis, demonstrate occurrence electron scattering in curved field down to energies 20 eV. We show that occurs closer sheet as energy decreases. The inflowing electrons, field‐aligned electrostatic...
Abstract Pulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies a few keV to tens keV) through wave-particle interactions, thereby depositing most their energy at altitudes ~ 100 km. However, maximum precipitated and its impacts on atmosphere unknown. Herein, we report unique observations European Incoherent Scatter (EISCAT) radar showing electron ranging from hundred MeV during PsA associated with weak geomagnetic storm. Simultaneously,...
Abstract Energetic electron precipitation from Earth’s outer radiation belt heats the upper atmosphere and alters its chemical properties. The precipitating flux intensity, typically modelled using inputs high-altitude, equatorial spacecraft, dictates belt’s energy contribution to strength of space-atmosphere coupling. classical quasi-linear theory through moderately fast diffusive interactions with plasma waves predicts that fluxes cannot exceed electrons trapped in belt, setting an...
Abstract Strong Thermal Emission Velocity Enhancement (STEVE) is a latitudinally narrow, purple‐band emission observed at subauroral latitudes. Stable Auroral Red (SAR) arcs characterized by major red emission, and red/green with both green emissions also occur Characteristics of magnetospheric source plasma electromagnetic fields these three types have not been fully understood because the limited conjugate observations between magnetosphere ground. In this study, we report 11 (2 STEVEs, 7...
At ~25 km altitude over magnetic anomalies on the Moon, deceleration of solar wind ions, acceleration electrons parallel to field, and heating ions reflected by were simultaneously observed MAP-PACE Kaguya. Deceleration was for two major ion compositions: protons alpha particles. had same ΔE /q (ΔE: energy, q: charge) both In addition, energy almost as ions. This indicates existence an anti-moonward electric field anomaly above The in a much larger area than where enhancement observed. These...
The first-order Fermi acceleration of electrons requires an injection into a mildly relativistic energy range. However, the mechanism has remained puzzle both in theory and observation. We present direct evidence for novel stochastic shock drift obtained with Magnetospheric Multiscale observations at Earth's bow shock. theoretical model can explain electron to energies high-speed astrophysical shocks, which may provide solution long-standing issue injection.
The Moon has no global intrinsic magnetic field and only a very thin atmosphere. Ion measurements made from lunar orbit provide us with information regarding interactions between the solar wind planetary surface, surface composition through secondary ion mass spectrometry source loss mechanisms of tenuous An energy spectrometer MAP‐PACE IMA onboard orbiter SELENE (KAGUYA) detected low‐energy ions at 100‐km altitude. have elucidated that originate exosphere are least composed He + , C O Na K...
We study solar wind (SW) entry deep into the near‐Moon wake using SELENE (KAGUYA) data. It has been known that SW protons flowing around Moon access central region of distant lunar wake, while their intrusion never expected. show sneak deepest (anti‐subsolar at ∼100 km altitude), and yields strong asymmetry environment. Particle trajectory calculations demonstrate these are once scattered dayside surface, picked‐up by motional electric field, finally wake. Our results mean surface coming...
In contrast to many ground‐based optical observations of the thin lunar alkali exosphere, in situ exospheric ions by satellite‐borne plasma instruments have been quite rare. MAP‐PACE‐IMA onboard Japanese orbiter SELENE (KAGUYA) succeeded detecting Moon originating at 100 km altitude. Here we make first report ion detection during intervals when was embedded Earth's magnetotail lobe. absence effects on source process, species H + , He ++ C O Na K and Ar are definitively identified. The fluxes...
The medium-energy particle experiments–ion mass analyzer (MEP-i) was developed for the exploration of energization and radiation in geospace (ERG) mission (Arase), order to measure three-dimensional distribution functions inner-magnetospheric ions medium energy range between 10 180 keV/q. energy, mass, charge state each ion are determined by a combination an electrostatic energy/charge analyzer, time-of-flight mass/charge energy-sensitive solid-state detectors. This paper describes...
Low-energy ion experiments–ion mass analyzer (LEPi) is one of the particle instruments onboard ERG satellite. LEPi an energy-mass spectrometer which covers range energies from < 0.01 to 25 keV/q. Species incoming ions are discriminated by a combination electrostatic energy-per-charge analysis and time-of-flight technique. The sensor has planar field-of-view, provides 4 $$\pi$$ steradian coverage using spin motion started its nominal observation after initial checkout commissioning phase in space.
Two-step energy transfer in space plasma Plasmas are ionized gases that contain negative electrons, positive ions, and electromagnetic fields. These constituents can oscillate position over time, carrying as waves. In principle, such waves could between two different ion populations. Kitamura et al. analyzed data from the Magnetospheric Multiscale mission, a group of four spacecraft flying tight formation through Earth's magnetosphere. They discovered an event which was transferred hydrogen...
Abstract The science operations of the spacecraft and remote sensing instruments for Martian Moon eXploration (MMX) mission are discussed by operation working team. In this paper, we describe Phobos observations during first 1.5 years spacecraft’s stay around Mars, Deimos before leaving system. observation, will be placed in low-altitude quasi-satellite orbits on equatorial plane make high-resolution topographic spectroscopic surface from five different altitudes orbits. also attempt to...
We study solar wind (SW) intrusion into the near‐Moon wake using SELENE (KAGUYA) data. It has been known that SW protons are gradually accelerated toward center along magnetic field in distant lunar wake, while never measured. show come at ∼100 km altitude direction perpendicular to field, as they gain kinetic energy one hemisphere lose other hemisphere. Particle trajectory calculations and theoretical treatment demonstrate proton Larmor motions inward electric around boundary result loss of...
Abstract The Magnetospheric Multiscale mission has demonstrated the frequent presence of reconnection exhausts at thin current sheets within Kelvin‐Helmholtz (KH) waves flank magnetopause. Motivated by these recent observations, we performed a statistical analysis boundary layers on magnetosheath side all KH 8 September 2015. We show 86% consistency between exhaust flows and particle leakage in but further highlight very additional layer signatures that do not come from locally observed...