Related papers: Temperature distribution of a non-flaring active r…
A key goal of the Solar Orbiter mission is to connect elemental abundance measurements of the solar wind enveloping the spacecraft with EUV spectroscopic observations of their solar sources, but this is not an easy exercise. Observations…
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 of the chromosphere and transition region to nanoflares, as…
We report the detection of emission from a non-thermal electron distribution in a small solar microflare (GOES class A5.7) observed by the Nuclear Spectroscopic Telescope Array (NuSTAR), with supporting observation by the Reuven Ramaty High…
Coronal loops are the basic structures of the solar transition region and corona. The understanding of physical mechanism behind the loop heating, plasma flows, and filling are still considered a major challenge in the solar physics. The…
A comprehensive study of the physical parameters of active region fan loops is presented using the observations recorded with the Interface Region Imaging Spectrometer (IRIS), the EUV Imaging Spectrometer (EIS) on-board Hinode and the…
The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…
The solar corona is much hotter than the photosphere and chromosphere, but the physical mechanism responsible for heating the coronal plasma remains unidentified yet. The thermal microwave emission, which is produced in strong magnetic…
Microflares are energetically smaller versions of solar flares, demonstrating the same processes of plasma heating and particle acceleration. However, it remains unclear down to what energy scales this impulsive energy release continues,…
Constraining the frequency of energy deposition in magnetically-closed active region cores requires sophisticated hydrodynamic simulations of the coronal plasma and detailed forward modeling of the optically-thin line-of-sight integrated…
Microflares have been considered to be among the major energy input sources to form active solar corona. To investigate the response of the low atmosphere to events, we conducted an ALMA observation at 3 mm coordinated with IRIS and Hinode…
It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun's hot corona, but whether they are the explanation for most of the multi-million degree plasma has been a matter of…
The impulsive phase of solar flares is a time of rapid energy deposition and heating in the lower solar atmosphere, leading to changes in the temperature and density structure of the region. We use an O V density diagnostic formed of the…
(Abridged abstract) We present an analysis of the X-ray emission of the rapidly rotating giant star YY Mensae observed by Chandra HETGS and XMM-Newton. Although no obvious flare was detected, the X-ray luminosity changed by a factor of two…
We present the results of a Suzaku spectroscopic study of the soft extended X-ray emission in the HII region M17. The spectrum of the extended emission was obtained with a high signal-to-noise ratio in a spatially-resolved manner using the…
In this paper we present the differential emission measures (DEMs) of two sub-A class microflares observed in hard X-rays (HXRs) by the FOXSI-2 sounding rocket experiment, on 2014 December 11. The second FOXSI (Focusing Optics X-ray Solar…
Inverse problems are of great importance in astrophysics for deriving information about the physical characteristics of hot optically thin plasma sources from their EUV and X-ray spectra. We describe and test an iterative method developed…
Recent imaging observations of EUV line emissions have shown evidence for frequent flare-like events in a majority of the pixels in quiet regions of the solar corona. The changes in coronal emission measure indicate impulsive heating of new…
In a previous paper we have described a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line…
Recently, it has been proposed that the magnetic-field-induced transition (MIT) in Fe X can be used to measure coronal magnetic field strengths. Several techniques, the direct line ratio technique and the weak and strong magnetic field…
In this study, the physics of sheath formation in a collisional two-electron temperature plasma in the presence of an oblique external magnetic field has been investigated. At first, a comparative study among the fluid electron model,…