93 citations · 292 across the 22 of their papers we have counts for
23 papers
Evidence for anisotropic non-Maxwellian velocity distributions in the solar transition region
Paola Testa, Bart De Pontieu, Kyuhyoun Cho +2
Spectroscopic observations of the solar transition region have long shown excess line broadening and non-Gaussian profiles, but their spatial distribution and prevalence are not we…
Predicting the thermodynamics in the chromosphere from the translation of SDO data into the IRIS inversion results using a visual transformer model
Alberto Sainz Dalda, Vishal Upendran, Juno Kim +4
We present SDO2IRIS: a visual transformer model that translates a combination of images of the chromosphere and transition region (TR), observed by AIA, and a line-of-sight mag…
Coronal Abundance Fractionation Linked to Chromospheric Transverse MHD Waves in a Solar Active Region Observed with FISS/GST and EIS/Hinode
Kyoung-Sun Lee, Jongchul Chae, Hannah Kwak +5
Elemental abundances in the solar corona differ from those in the photosphere, with low first ionization potential (FIP) elements being enhanced, a phenomenon known as the FIP effe…
On the Nature of Nonthermal Broadening of Spectral Lines Observed by IRIS
Kyuhyoun Cho, Bart De Pontieu, Paola Testa
The origin of nonthermal broadening in solar spectra is one of the long-standing questions in solar physics. Various processes have been invoked - including unresolved flows, waves…
A model of umbral oscillations inherited from subphotospheric fast-body modes
Juhyung Kang, Jongchul Chae, Kyuhyoun Cho +2
Recently, complex horizontal patterns of umbral oscillations have been reported, but their physical nature and origin are still not fully understood. Here we show that the two-dime…
Large-amplitude transverse MHD waves prevailing in the H chromosphere of a solar quiet region revealed by MiHI integrated field spectral observations
Jongchul Chae, Michiel van Noort, Maria S. Madjarska +3
The investigation of plasma motions in the solar chromosphere is crucial for understanding the transport of mechanical energy from the interior of the Sun to the outer atmosphere a…
A Statistical Study of IRIS Observational Signatures of Nanoflares and Non-thermal Particles
Kyuhyoun Cho, Paola Testa, Bart De Pontieu +1
Nanoflares are regarded as one of the major mechanisms of magnetic energy release and coronal heating in the solar outer atmosphere. We conduct a statistical study on the response…
Investigation of the subsurface structure of a sunspot based on the spatial distribution of oscillation centers inferred from umbral flashes
Kyuhyoun Cho, Jongchul Chae, Maria S. Madjarska
The subsurface structure of a solar sunspot is important in the stability of the sunspots and the energy transport therein. Two subsurface structure models have been proposed, the…
The chromospheric component of coronal bright points. Coronal and chromospheric responses to magnetic-flux emergence
Maria S. Madjarska, Jongchul Chae, Fernando Moreno-Insertis +5
We investigate the chromospheric counterpart of small-scale coronal loops constituting a coronal bright point (CBP) and its response to a photospheric magnetic-flux increase accomp…
Impulsive wave excitation by rapidly changing granules
Hannah Kwak, Jongchul Chae, Maria S. Madjarska +2
It is not yet fully understood how magnetohydrodynamic waves in the interior and atmosphere of the Sun are excited. Traditionally, turbulent convection in the interior is considere…
Inference of chromospheric plasma parameters on the Sun
Jongchul Chae, Maria S. Madjarska, Hannah Kwak +1
The solar chromosphere can be observed well through strong absorption lines. We infer the physical parameters of chromospheric plasmas from these lines using a multilayer spectral…
The Application of the Filtered Backprojection Algorithm to Solar Rotational Tomography
Kyuhyoun Cho, Jongchul Chae, Ryun-Young Kwon +2
Solar rotational tomography (SRT) is an important method to reconstruct the physical parameters of the three-dimensional solar corona. Here we propose an approach to apply the filt…
Strong Blue Asymmetry in Hα line as a Preflare Activity
Kyuhyoun Cho, Jeongwoo Lee, Jongchul Chae +5
Chromospheric activities prior to solar flares provide important clues to solar flare initiation, but are as yet poorly understood. We report a significant and rapid H line broa…
Source Depth of Three-minute Umbral Oscillations
Kyuhyoun Cho, Jongchul Chae
We infer the depth of the internal sources giving rise to three-minute umbral oscillations. Recent observations of ripple-like velocity patterns of umbral oscillations supported th…
Positive and negative feedback of AGN outflows in NGC 5728
Jaejin Shin, Jong-Hak Woo, Aeree Chung +4
We present a spatially-resolved analysis of ionized and molecular gas in a nearby Seyfert 2 galaxy NGC 5728, using the VLT/MUSE and ALMA data. We find ionized gas outflows out to ~…
The Observational Evidence for the Internal Excitation of Sunspot Oscillations Inferred from the Fe I 5435 A Line
Kyuhyoun Cho, Jongchul Chae, Eun-kyung Lim +1
The umbral oscillations of velocity are commonly observed in the chromosphere of a sunspot. Their sources are considered to be either the external p-mode driving or the internal ex…
The Physical Nature of Spiral Wave Patterns in Sunspots
Juhyung Kang, Jongchul Chae, Valery M. Nakariakov +3
Recently, spiral wave patterns (SWPs) have been detected in 3 minute oscillations of sunspot umbrae, but the nature of this phenomenon has remained elusive. We present a theoretica…
Observation of a Large-scale Quasi-circular Secondary Ribbon associated with Successive Flares and a Halo CME
Eun-Kyung Lim, Vasyl Yurchyshyn, Pankaj Kumar +7
Solar flare ribbons provide an important clue to the magnetic reconnection process and associated magnetic field topology in the solar corona. We detected a large-scale secondary f…
Chromospheric Plasma Ejections in a Light Bridge of a Sunspot
Donguk Song, Jongchul Chae, Vasyl Yurchyshyn +5
It is well-known that light bridges inside a sunspot produce small-scale plasma ejections and transient brightenings in the chromosphere, but the nature and origin of such phenomen…
A New Method to Determine the Temperature of CMEs Using a Coronagraph Filter System
Kyuhyoun Cho, Jongchul Chae, Eun-kyung Lim +3
The coronagraph is an instrument enables the investigation of faint features in the vicinity of the Sun, particularly coronal mass ejections (CMEs). So far coronagraphic observatio…
Ultra-narrow Negative Flare Front Observed in Helium-10830~Å using the 1.6 m New Solar Telescope
Yan Xu, Wenda Cao, Mingde Ding +10
Solar flares are sudden flashes of brightness on the Sun and are often associated with coronal mass ejections and solar energetic particles which have adverse effects in the near E…
Observations of a Series of Flares and Associated Jet-like Eruptions Driven by the Emergence of Twisted Magnetic Fields
Eun-Kyung Lim, Vasyl Yurchyshyn, Sung-Hong Park +8
We studied temporal changes of morphological and magnetic properties of a succession of four confined flares followed by an eruptive flare using the high-resolution New Solar Teles…
Chromospheric Sunspot Oscillations in H-alpha and Ca II 8542A
Ram Ajor Maurya, Jongchul Chae, Hyungmin Park +3
We study chromospheric oscillations including umbral flashes and running penumbral waves in a sunspot of active region (AR) using scanning spectroscopy in H-alpha and Ca II 8542A,…