A5056575139- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Solar Radiation and Photovoltaics
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Adaptive optics and wavefront sensing
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Hydrocarbon exploration and reservoir analysis
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Nuclear Physics and Applications
- Ocean Waves and Remote Sensing
- Spacecraft and Cryogenic Technologies
- Earthquake Detection and Analysis
- Spacecraft Design and Technology
- Astronomical Observations and Instrumentation
- solar cell performance optimization
- Satellite Image Processing and Photogrammetry
- Electrostatic Discharge in Electronics
- Radio Wave Propagation Studies
- Nuclear Engineering Thermal-Hydraulics
- Geophysics and Sensor Technology
Korea Astronomy and Space Science Institute
2013-2024
Korea University of Science and Technology
2014-2019
New Jersey Institute of Technology
2014-2016
Kyung Hee University
2001
This study reports comprehensive observations for the G5-level geomagnetic storm that occurred from May 10 to 12, 2024, most intense event since 2003 Halloween storm. The was triggered by a series of coronal mass ejections (CMEs) originating merging two active regions 13664/13668, which formed large and complex photospheric magnetic configuration produced X-class flares in early 2024. Among events, significant CME, driven an X2.2 flare on 9, caught up with merged preceding slower CME...
Abstract We present the morphological and kinematic characteristics of three small-scale X-ray/EUV jets simultaneously observed by Hinode XRT TRACE. For this, we examined all movies with a thin Al/Poly filter from 2006 October 20 to 2007 April 8, then found 34 eruptions. next took look at corresponding TRACE 171/195 Å images associated As result, simultaneous X-ray EUV jets. two different bands, they have similar in terms projected speed (90–310 km s$^{-1}$), lifetime (100–2000 s), size...
We present a morphological study of the 2004 August 18 solar eruption that occurred in active region NOAA 10656 near west limb using extreme-ultraviolet (EUV) data from Transition Region and Coronal Explorer (TRACE), Hα filtergram Big Bear Solar Observatory, white light images Mauna Loa Observatory (MLSO), hard X-ray (HXR) Reuven Ramaty High Energy Spectroscopic Imager (RHESSI), microwave Owens Valley Array. In this event, we have an excellent set observations for tracing early evolution...
To better understand a preferred magnetic field configuration and its evolution during Coronal Mass Ejection events, we investigated the spatial temporal of photospheric fields in active region NOAA 9236 that produced eight flare-associated CMEs time period 2000 November 23-26. The variations total helicity injection rate unsigned flux are determined examined not only entire but also some local regions such as main sunspots CME-associated flaring using SOHO/MDI magnetogram data. As result,...
We report three-minute oscillations in the solar chromosphere driven by a strong downflow event sunspot. used Fast Imaging Solar Spectrograph of 1.6 m New Telescope and Interface Region (IRIS). The is identified chromospheric transition region lines above sunspot umbra. After event, occur at same region. amplitude Doppler velocity 2 km/s, gradually decreases with time. In addition, period increases from 2.7 minutes to 3.3 minutes. IRIS 1330 slit-jaw images, we identify transient brightening...
Abstract Understanding the formation of post-CME blobs, we investigate 2 blobs in outer corona observed by LASCO-C2 and 34 inner K-Cor on 2017 September 10 from 17:11 to 18:58 UT. By visual inspection structure a current sheet (CS) its associated find that CS is well identified radial lengths are nine times longer than lateral widths, indicating unstable linear tearing mode. The can be classified into two groups: 27 generated middle (Group 1) 7 occurred above tips it 2). Their widths <?CDATA...
Abstract We present one Hinode Spectropolarimeter (SP) magnetogram of AR 10930 that produced several major flares. The inversion from Stokes profiles to magnetic field vectors was made using the standard Milne-Eddington code. successfully applied Uniform Shear Method for resolving 180$^{\circ}$ ambiguity magnetogram. gave very strong strengths (near 4500 gauss) a small portion area in umbra. Considering observed V-profile 6301.5 Å well-fitted as well direct estimation Zeeman splitting...
We studied temporal changes of morphological and magnetic properties a succession four confined flares followed by an eruptive flare using the high-resolution New Solar Telescope (NST) operating at Big Bear Observatory (BBSO), Helioseismic Magnetic Imager (HMI) magnetograms Atmospheric Image Assembly (AIA) EUV images provided Dynamics (SDO). From NST/Halpha SDO/AIA~304 A observations we found that each developed jet structure evolved in manner similar to evolution blowout : 1) inverted-Y...
Using the MHD coronal seismology technique, we estimated magnetic field for three spicules observed in 2008 June. For this study, used high resolution Ca II H line (<TEX>$3968.5\;{\AA}$</TEX>) images by Hinode SOT and considered a vertical thin flux tube as spicule model. To our knowledge, is first attempt to estimate using observation. From oscillation properties, determined periods, amplitudes, minimum wavelengths, wave speeds. We interpreted oscillations kink waves propagating through...
Abstract During transient events such as major solar eruptions, the plasma can be far from equilibrium ionization state because of rapid heating or cooling. Nonequilibrium (NEI) is important in rapidly evolving systems where thermodynamical timescale shorter than recombination timescales. We investigate effects NEI on EUV and X-ray observations by Atmospheric Imaging Assembly (AIA) board Solar Dynamic Observatory Telescope (XRT) Hinode . Our model assumes that initially at low temperature,...
The study of pores, small penumbraless sunspots, can give us a chance to understand how strong magnetic fields interact with convective motions in the photosphere. For better understanding this interaction, we investigate temporal variation several tiny pores smaller than 2''. These were observed by Solar Optical Telescope on board Hinode 2006 December 29. We have analyzed high-resolution spectropolarimetric (SP) data and G-band filtergrams taken during observation. Magnetic flux density...
Abstract Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical thermal instabilities. Such instabilities important because they may be responsible for energy transport and conversion. We present a clear observation of streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place prominence using the H α Lyot filter installed at New Vacuum Solar Telescope, Fuxian-lake Observatory Yunnan, China. On one side prominence, series...
Abstract We report on the successive occurrence of 0.″5 wide photospheric vortices with strong transverse shear flows at edge a sunspot light bridge (LB), and subsequent ejection chromospheric surges observed using Visible Inteferometry Spectrograph, broadband TiO filter, Near InfRared Imaging Spectrograph Goode Solar Telescope operating Big Bear Observatory. The H α ejected location often appeared in hollow cylindrical structure. also quasi-periodic vortex-associated bright plasma blobs...
The COronal Diagnostic EXperiment (CODEX) is a Heliophysics mission to measure the density, temperature, and velocity of electrons in solar corona with primary goal improving our understanding physical conditions wind acceleration region. temperature measurement requires much higher signal-to-noise ratio than density measurements. In coronagraphs, diffraction disk light due occulting element dominant source noise. Therefore, further suppress diffracted sun respect existing coronagraphs...
ABSTRACT We investigate the photospheric and magnetic field structures associated with Ellerman bombs (EBs) using 1.6 m New Solar Telescope at Big Bear Observatory. The nine observed EBs were accompanied by elongated granule-like features (EGFs) that showed transverse motions prior to an average speed of about 3.8 km s −1 . Each EGF consisted a sub-arcsecond bright core encircled dark lane around its moving front. appeared in TiO broadband filter images far wings H α Ca ii 8542 Å lines. In...
Abstract The propagating intensity disturbances (PIDs) in plumes are still poorly understood, and their identity (magnetoacoustic waves or flows) remains an open question. We investigate PIDs five located the northern polar coronal hole observed during 2017 total solar eclipse. Three associated with bright points, jets, macrospicules at base (active plumes), other two not (quiet plumes). electron temperature of is obtained from filter ratio images taken X-ray Telescope on board Hinode...
Abstract We investigated the evolution of a C3.3 impulsive flare and its preflare activity, which occurred in NOAA Active Region 10923 on 2006 November 12, using Hinode X-Ray Telescope (XRT) data. For an extensive investigation, we also used GOES X-ray flux, TRACE 171 Å, SOHO MDI Examining time-series XRT images, can identify following evolutionary sequences: (1) There were three bundles loops along sheared polarity inversion line forming sigmoidal structure during phase. (2) Preflare...
A new type of chromospheric jets in a polar limb coronal hole is discovered the Ca II filtergram Solar Optical Telescope on board \textit{Hinode}. We identify 30 movie duration 53 min. The average speed at their maximum heights found to be 132$\pm$44 km s$^{-1}$ ranging from 57 264 along propagation direction. lifetime 20$\pm$6 11 seconds 36 seconds. and are located end-tails those parameters determined for spicules, hence implying jets. To confirm whether these different conventional we...
X-ray plasma ejections often occurred around the impulsive phases of solar flares and have been well observed by SXT aboard Yohkoh. Though show various morphological shapes, there has no attempt at classifying groups for a large sample ejections. In this study, we classified 137 according to their shape first time. Our classification criteria are as follows: (1) loop type shows ejecting with loops, (2) spray continuous stream without showing any typical shape, (3) jet collimated motions...
We report the first simultaneous observation of X-ray plasma ejection (XPE), coronal mass (CME), and type II solar radio burst on 1999 October 26. First, an XPE was observed from 21:12 UT to 21:24 in Yohkoh SXT field view (1.1 1.4 R☉). The accelerated with a speed range 190 410 km s−1 its average is about 290 s−1. Second, associated CME by Mauna Loa Mk4 coronameter (1.1–2.8 R☉) 21:16 UT. front clearly identified at 21:26 propagated deceleration −110 m s−2. Its 360 At start time (21:25 UT),...
We investigate the solar cycle variation of microwave and extreme ultraviolet (EUV) intensity in latitude to compare polar brightening (MPB) with EUV coronal hole (CH). For this study, we used full-sun images observed 17 GHz Nobeyama Radioheliograph from 1992 July 2016 November two channels Atmospheric Imaging Assembly (AIA) <TEX>$193{\AA}$</TEX> <TEX>$171{\AA}$</TEX> on Solar Dynamics Observatory (SDO) 2011 January November. As a result, found that is anti-correlated microwave. Since...