A5040153696- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Luminescence Properties of Advanced Materials
- Atmospheric Ozone and Climate
- Magnetic confinement fusion research
- Thin-Film Transistor Technologies
- Silicon Nanostructures and Photoluminescence
- Carbon Nanotubes in Composites
- Ga2O3 and related materials
- Tropical and Extratropical Cyclones Research
- GaN-based semiconductor devices and materials
Heliophysics
2024
Catholic University of America
2020-2024
Goddard Space Flight Center
2016-2024
University of America
2020-2024
Kumho Petrochemical (South Korea)
2008-2015
Chungnam National University
2015
Abstract We use global and local hybrid (kinetic ions fluid electrons) simulations to investigate the conditions under which foreshock bubbles (FBs) form how their topology changes with solar wind conditions. FBs as a result of interaction between discontinuities backstreaming ion beams in foreshock. They consist an outer shock its associated sheath plasma low density high temperature core magnetic field strength. The structure is determined by angle interplanetary normal discontinuity. show...
Abstract Using a three‐dimensional (3‐D) global‐scale hybrid code, the Magnetospheric Multiscale (MMS) reconnection event around 02:13 UT on 18 November 2015, highlighted in Geospace Environment Modeling (GEM) Dayside Kinetic Challenge, is simulated, which interplanetary magnetic field (IMF) points southward and geomagnetic has −27° dipole tilt angle. Strong plasma jets are found near magnetopause as result of dayside reconnection. Our results indicate that subsolar X line shifts from point...
Abstract Foreshock bubbles (FBs) form as a result of the interaction between solar wind discontinuities and backstreaming ion beams in foreshock. They are carried by anti‐sunward direction associated with high energy ions. We employ electromagnetic hybrid (kinetic ions, fluid electrons) simulations test particle calculations to investigate acceleration FBs. Simulation results show that maximum energies which ions attain not sensitive topology FBs, varies from spherical planar limits....
Abstract A three‐dimensional global hybrid simulation is conducted for the interaction of Earth's bow shock with an interplanetary directional tangential discontinuity (TD) whose normal lies in equatorial plane. Although convection electric field points into TD from its trailing side both north and south equator, only generates a hot flow anomaly (HFA) southern hemisphere. HFA generation results shock‐reflected ions energized by inward‐pointing on one inward ion gyration other side. The...
In 1961, Dungey suggested that magnetic reconnection occurs due to the solar-terrestrial interaction. The interplanetary field (IMF) is thought merge with Earth’s geomagnetic (GMF). After process newly formed flux tube, consisting of both IMF and GMF, moves anti-sunward. Poleward-moving auroral forms (PMAFs) are believed be ionospheric signatures this process, which transfers from dayside nightside. This paper looks at connection between solar wind speed motion PMAF as it oval, anti-sunward,...
Abstract Transient events like hot flow anomalies and foreshock bubbles are common in the Earth's foreshock. These transients may play an important role solar wind‐magnetosphere interaction. They typically occur when backstreaming ions accumulate at intersection of interplanetary magnetic field (IMF) discontinuities with bow shock. Discontinuity orientations a key determining where form strike magnetopause. also amplitude, significance, individual transients. We investigate properties IMF...
Abstract Global hybrid code simulations predict enhanced densities and magnetic field strengths not only in foreshock compressional boundaries on the flanks of steady‐state dayside under near‐radial IMF conditions but also edges traveling cavities formed when slabs interplanetary (IMF) lines connect to bow shock. The modest velocity or temperature perturbations attending compressional/cavity boundaries. However, they pronounced flow enhancements depressed temperatures accompanying...
Abstract The effect of substitution Sr 2+ by Mg on the luminescence properties (Sr 0.9 − x )Si 2 O N :0.1Eu were investigated as a function concentration ( ). peak position yellowish green emission from was invariant with . However, intensity significantly affected With increasing concentration, increased to maximum at = 0.1. Partial enhanced 1.8‐fold. Eu positions both and excitation. red‐shifting enhancement associated nephelauxetic effect. Concentration quenching occurred above y 0.07 in...
Abstract We present multi‐point observations of foreshock bubbles (FBs) for comparison with the predictions hybrid simulations. The four Magnetospheric Multiscale (MMS) spacecraft observed a series discontinuities in region upstream from bow shock on December 18, 2017. Two solar wind were associated fully developed FBs core regions exhibiting greatly decelerated and deflected antisunward flows, significant increases temperature, depressed plasma densities magnetic field strengths. A single...
Abstract We present a case study of energetic ions observed by the Energetic Particle Detector (EPD) on Magnetospheric Multiscale spacecraft in magnetosheath just outside subsolar magnetopause that occurred at 1000 UT 8 December 2015. As receded inward, EPD burst (∼50–1000 keV) proton, helium, and oxygen exhibited an inverse dispersion, with lowest energy appearing first. The prolonged interval fast antisunward flow transient increases H components global ground magnetograms demonstrate...
Abstract We use the three‐dimensional (3‐D) global hybrid code ANGIE3D to simulate interaction of four solar wind tangential discontinuities (TDs) observed by ARTEMIS P1 from 0740 UT 0800 on 28 December 2019 with bow shock, magnetosheath, and magnetosphere. demonstrate how produce foreshock transients, a magnetosheath cavity‐like structure, brief magnetopause crossing THEMIS MMS spacecraft 0830 UT. D entries into transients exhibiting low density, magnetic field strength, high temperature...
Abstract Bursty reconnection models predict that flux transfer events (FTEs) moving along the magnetopause launch fast mode compressional waves into magnetosheath push bow shock outward. By contrast, increases in solar wind density striking should boundary inward and propagate across magnetosheath, drive on magnetopause, generate transient outer magnetosphere. Multipoint ACE, Wind, THEMIS, GOES‐11/12 wind, shock, magnetospheric observations 14 October 2008 provide direct evidence for...
Abstract The four Magnetospheric Multiscale (MMS) spacecraft observed energetic ( keV) ion bursts exhibiting an inverse dispersion in the magnetosheath on 28 December 2015. We consider possibility that these ions originate from magnetosphere. composition ratios, flux levels, and spectral slopes of energy spectra foreshock resemble those outer magnetosphere but differ significantly seen further upstream bow shock at ACE. particle gyrocenters lie earthward spacecraft, indicating maximum fluxes...
Abstract The four Magnetospheric Multiscale (MMS) spacecraft observed a ∼1 min burst of energetic ions (50–1000 keV) in the region upstream from subsolar quasi‐perpendicular bow shock on 6 December 2015. composition, flux levels, and spectral indices these protons, helium, oxygen greatly resemble those seen outer magnetosphere earlier while MMS crossed magnetopause differ significantly simultaneously far by Advanced Composition Explorer (ACE). However, event cannot be explained solely terms...
Abstract On 12 November 2015 the Magnetospheric Multiscale (MMS) spacecraft traversed magnetopause from magnetosphere to magnetosheath encountering evidence of magnetic reconnection and a tiny flux transfer event (FTE) on side boundary layer. The FTE exhibited large negative‐positive bipolar variation in normal field component ( B N ), an enhanced (negative) north‐south direction L third M resembling “W” shape with negative values close edges positive near center. Using tetrahedron...
Abstract Foreshock bubbles (FBs) occur when interplanetary magnetic field discontinuities encounter the Earth's foreshock. These transient (∼1 to 5 min) features exhibit depressed densities and strengths, enhanced temperatures, deflected plasma flows trailed by a region of density strength. Ions can be accelerated inside FBs through Fermi acceleration process. Hybrid simulations test particle calculations predict that maximum energies ions reach 5.6 times solar wind ram energy ( E sw ). We...
Abstract In this paper, we investigated the field emission properties of planar gate structure, which is and cathode electrode (buffer electrode) formed on same face glass. Emitters buffer electrodes were by screen printing method, has many advantages in a large size panel. CNT emitter was both electrodes. Bi‐polar pulses applied to high voltage DC power anode. case bi‐polar pulse for electron beam spreads more than normal structure or diode structure. It noted that increasing uniformity at...