A5043837903- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Spacecraft Design and Technology
- Plasma Diagnostics and Applications
- Earthquake Detection and Analysis
- Magnetic confinement fusion research
- Space exploration and regulation
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Satellite Communication Systems
- Neutrino Physics Research
- GNSS positioning and interference
- Educational Research and Pedagogy
- Magnetic Field Sensors Techniques
- Atmospheric aerosols and clouds
- Educational Robotics and Engineering
- Technology Assessment and Management
- Atomic and Subatomic Physics Research
- Engineering Education and Curriculum Development
- Planetary Science and Exploration
- Modular Robots and Swarm Intelligence
- Greenhouse Technology and Climate Control
- Atmospheric chemistry and aerosols
College of Industrial Technology
2021-2024
National Institute of Technology, Kochi College
2011-2021
National Institute of Technology, Kagoshima College
2020-2021
Metropolitan College
2021
National Institute of Technology
2017-2020
Space Micro (United States)
2017
Toho University
2014
Japan Aerospace Exploration Agency
2007-2010
Institute of Space and Astronautical Science
2007-2010
Space Research Institute
2004-2009
Abstract. Thirty rapid crossings of the magnetotail current sheet by Cluster spacecraft during July-October 2001 at a geocentric distance 19 RE are examined in detail to address structure sheet. We use four-point magnetic field measurements estimate electric density; spatial scale is estimated integration translation velocity calculated from temporal and derivatives. The local normal-related coordinate system for each case defined combining Minimum Variance Analysis (MVA) curlometer...
Chen and Wolf (1999) used a thin‐filament theory to construct 2D model of bursty bulk flow (BBF) motion inside the plasma sheet. The modeling revealed that low‐entropy filament overshoots its equilibrium position executes heavily damped oscillation about position. In this letter we demonstrate, for first time, multiple overshoot rebound BBF observed by five THEMIS probes on 17 March 2008 just after 10:22 UT. We found oscillatory braking was accompanied interlaced enhancements depletions...
Cluster multisatellite observations provide snapshots of electron distributions around the magnetic neutral line. An isotropic flat‐top‐type distribution in phase space is frequently observed X line, together with large ion velocities and a Hall quadrupole‐like field inside hot tenuous plasma sheet magnetotail. The flat‐top are also associated finite direction normal to sheet, cross‐tail current density sometimes very small. These results indicate that mainly located near outer boundary...
We present Cluster multisatellite observations of accelerated electrons in the near‐Earth magnetotail associated with substorms. found that hardest electron energy spectra appear earliest stage substorm expansion tail region and they gradually become softer during events. Enhancement high‐energy flux occurs generally bulk acceleration ions (fast flow) electrons. It is also shown sometimes show preferential perpendicular temporal enhancement normal component magnetic field, then anisotropic...
On 17 March 2008 around 0912 UT the five THEMIS spacecraft P1–P5 were in plasma sheet between 2200 and 2300 h magnetic local time (MLT), covering radial distances 15 Earth radii (Re) (P1) 9 Re (P5). All consecutively observed a bursty bulk flow (BBF) that traveled earthward, slowed down from 400 km/s to 50 P1 P5, then turned opposite direction. The most tailward‐located spacecraft, P2, detected thinning thickening of direction change. Meanwhile, other three which located more dipolar region,...
We examined the relationship between bursty bulk flow (BBF) events observed by Cluster −19 R E < X −12 and dipolarization Double Star TC1 −13 −6 . dipolarizations for ∼33% of cases when BBFs were Cluster. During these location was closer to local B Z at smaller than during where no clear associated with This result suggests that (1) flow‐associated activity dissipates within a limited spatial scale, 4–8 , (2) initial magnetic topology in inner magnetosphere can contribute strongly fast...
Abstract. Simultaneous observations by the Cluster spacecraft and SuperDARN radars are presented of magnetotail flux transport during northward, but BY-dominated IMF. Two events discussed, which occurred on 14 August 2004 17 September 2005, intervals negative positive IMF BY, respectively. During both observed isolated bursts Earthward plasma convection in central sheet. first event, flows also had a significant V⊥Y component duskward direction, consistent with westward azimuthal midnight...
Generally, windows in greenhouses are automatically opened and closed to regulate the internal temperature. However, because air outside during winter Japan is dry, opening reduce temperature causes humidity deficit increase above 6 g/m3, thereby inhibiting plant growth. Therefore, this study, we developed a model that considers effects of weather sampling period using subspace (N4SID) method based on environmental data from inside greenhouse winter. By adopting data-driven model, models for...
Abstract. This article describes observations of a bursty bulk flow (BBF) in the outer central plasma sheet. The are made with Cluster satellites, located approximately 19 RE downtail, close to midnight sector Southern Hemisphere. 40–60 s after first detected BBF, there was large bipolar perturbation magnetic field. A Grad-Shafranov reconstruction has revealed that this is created by field-aligned current at flank BBF. Further analysis moments shown BBF properties depleted flux tube....
The Kelvin‐Helmholtz instability (KHI) on the boundary of a flow channel in Earth's plasma sheet is investigated using Cluster and Double Star TC1 data. It shown that when moves into magnetometer measures strong oscillations magnetic field, increase as spacecraft move further channel. These waves are identified Kelvin Helmholtz waves. DoubleStar TC1, closer to Earth, also observes these entering but at larger amplitude with only little flow. wave agrees KHI growth. argued development can...
The passage of an interplanetary shock caused a sudden compression the magnetosphere between 0900 UT and 0915 on 24 August 2005. An estimate normal from solar wind data obtained by Geotail upstream bow indicates symmetric with respect to noon‐midnight meridian. Compression‐related disturbances magnetic electric field plasma motion were observed Double Star Program (DSP) Tan Ce 1 (TC1) 2 (TC2) in inner Cluster spacecraft dawnside sheet. DSP/TC1 TC2 observations suggest that are propagating...
Abstract We present the simultaneous and conjugated auroral emission particle data obtained by a low‐altitude polar‐orbiting micro‐satellite, Reimei, for elucidating their latitudinal distributions variations in nightside oval. Here are reported few notable examples of Reimei observations with high time spatial resolutions, namely ∼120 msec. ∼1.2 km × 1.2 multispectral images 40 energy‐pitch angle electrons ions energies 10 eV–12 keV, respectively. The show various fine‐scale activities...
Statistical properties of low‐frequency (0.01–0.1 Hz) electromagnetic waves and their relations to ion distribution functions in “transition regions” from lobe the plasma sheet, which include sheet boundary layer (PSBL) are investigated based on 5‐year data Geotail spacecraft observations X GSM = [−31, −15] ∣ Y < 5 R E . It is shown that amplitude magnetic field fluctuations increases with increasing β (the ratio thermal pressure pressure), while electric decreases high‐β regions. These...
Abstract. On 14 August 2004 a large-scale magnetic structure was observed by Double Star TC-1 in the southern lobe and Cluster northern of magnetotail. The has signature (localized) dipolarization, decreasing Bx accompanied an increasing Bz strong earthward flow. propagation direction this structure, however, seems to be more dawnward than earthward. is ULF waves with period ~5 min, which are simultaneously ground magnetometer station DIK, at footpoints spacecraft. We interprete these as...
[1] Using the electron data from Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft measurements 2007 to 2009, we derived global phase space density (PSD) distributions plasma sheet electrons (2–100 eV/nT) examine transport process inner magnetosphere possible loss mechanisms convective transport. The boundaries were determined by observed compared with Alfvén that calculated sum simple corotation convection electric field models. This comparison confirms...
We present observations on 19–20 November 2006 by the Cluster spacecraft that were skimming high‐latitude dusk‐flank magnetopause, which are consistent with more than one reconnection X‐line tailward side of cusp under northward IMF. Evidence quasi‐continuous over 16 hours exists in form Alfvénic acceleration magnetosheath ions found almost always when either satellites traversed boundary. The data indicate a dominant was sunward for most time, but ion velocity distributions consisting two...
Abstract We present an event based on Reimei satellite observations in the low‐altitude midnight auroral region, showing that intense and clear energy‐dispersed electron precipitations, repetitively generated by field‐aligned accelerations due to dispersive Alfvén waves, were modulating inverted‐V electrons. These Alfvénic electrons had peak energies equal or slightly larger than those of inverted‐Vs associated with filamentary forms rapidly streaming at poleward edge a broad discrete arc....
In order to control electron energy distributions in discharge plasmas, we have developed a new hollow cathode with pins inside. With an increase the pin length, temperature is observed decrease continuously by of magnitude, being accompanied change local plasma structure, weakly magnetized low-pressure Ar dc plasmas.
Abstract. We studied two types of dipolarization events with different IMF conditions when Cluster and Double Star (TC-1) were located in the same local time sector: 7 August 2004, 18:00-24:00 UT, during a disturbed southward/northward interval, 14 21:00-24:00 was stably northward. observed as well fast flows both intervals, but this not case for TC-1. For satellites crossed near conjugate location MIRACLE stations. By using multi-point analysis techniques, direction/speed propagation is...
Abstract. Using Cluster multipoint magnetic and plasma measurements we analyze the spatial structure of flow-associated turbulence on 26 September 2005. The fortunate relative configuration spacecraft flow allowed for first time to compare scale evolution statistical moments both at boundary in central part same time. simultaneous increase skewness kurtosis over seconds provides evidence existence nonlocal coupling Earth's sheet.
[1] Fast azimuthal auroral expansion and poleward are characteristic features of the phase substorms. In first study its kind, we have investigated magnetospheric counterpart using data from Time History Events Macroscale Interactions during Substorms (THEMIS) all-sky imagers multiple spacecraft. During tail season in 2008–2009, found 16 events azimuthally expanding aurora that passed near magnetic footprints spacecraft operating near-Earth plasma sheet. magnetosphere, these commonly showed...
The "Conjunction Event Finder (CEF)" is a Web tool for seamlessly browsing quick-look (QL) data from many different kinds of satellites and ground-based instruments in solar-terrestrial physics. QL plots are generally scattered all over the world, so that them far very troublesome inefficient. Just simple procedure on CEF, however, generates collection links to period interest, allowing us check much more efficiently than ever. Hence this powerful finding interesting events conjunction...
Abstract. Electromagnetic low-frequency waves in the magnetotail lobe close to PSBL (Plasma Sheet Boundary Layer) are studied using Cluster spacecraft. The show Alfvénic properties and transport their wave energy (Poynting flux) on average toward Earth along magnetic field lines. Most of events rich with oxygen (O+) ion plasma. O+ plasma can serve enhance fluctuations, resulting a greater likelihood observation, but it does not appear be necessary for generation waves. Taking into account...
A dipolarization and its associated current systems are studied using Cluster, Double Star TC1, ground‐based observations. The Cluster spacecraft located approximately 16 R E downtail near 0030 LT. TC1 is more earthward at 7 just before local midnight. Auroral observations by the Wideband Imaging Camera on Imager for Magnetopause‐to‐Aurora Global Exploration used to determine onset times of substorms. It shown that magnetic phenomena site a reconfiguration region governed field‐aligned...