相关论文: Non-equilibrium ionization effects on solar EUV an…

I explore the thermal evolution and ionization states in gas cooling from an initially hot state in the presence of external photoionizing radiation. I compute the equilibrium and nonequilibrium cooling efficiencies, heating rates, and ion…

An analysis using modern atomic data of fluxes culled from the literature for O VIII and Ne IX lines observed in solar active regions by the P78 and Solar Maximum Mission satellites confirms that the coronal Ne/O abundance ratio varies by a…

The Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory obtains extreme-ultraviolet (EUV) spectra of the full-disk Sun at a spectral resolution of ~1 A and cadence of 10 s. Such a spectral resolution would…

Particle-in-cell direct simulation Monte Carlo simulations reveal that ion-acoustic instabilities excited in presheaths can cause significant ion heating. Ion-acoustic instabilities are excited by the ion flow toward a sheath when the…

The calculations of the ratios of the Helium-like ion X-ray lines from C V to Si XIII are revisited in order to apply the results to density, temperature and ionization process diagnostics of data from high-resolution spectroscopy of the…

Nonrelativistic electrostatic unmagnetized shocks are frequently observed in laboratory plasmas and they are likely to exist in astrophysical plasmas. Their maximum speed, expressed in units of the ion acoustic speed far upstream of the…

We have compiled a set of electron-impact multiple ionization (EIMI) cross sections for astrophysically relevant ions. EIMI can have a significant effect on the ionization balance of non-equilibrium plasmas. For example, it can be important…

The Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory is a state-of-the-art imager with the potential to do unprecedented time-dependent multi-thermal analysis at every pixel on scales short compared to the radiative…

The mixed morphology class of supernova remnants (MMSNRs) comprises a substantial fraction of observed remnants and yet there is as yet no consensus on their origin. A clue to their nature is the presence of regions that show X-ray evidence…

In the previous works the significance of the symmetric and non-symmetric ion-atom absorption processes in far UV and EUV regions within a model of the quiet Sun atmosphere, has been studied. The considered processes were the processes of…

In the work described here we investigate atomic processes leading to the formation of emission lines within the IRIS wavelength range at temperatures near $10^5$~K. We focus on (1) non-equilibrium and (2) density-dependent effects…

This paper investigates a quiescent (non-flaring) active region observed on July 13, 2010 in EUV, SXR, and HXRs to search for a hot component that is speculated to be a key signature of coronal heating. We use a combination of RHESSI…

We review the presence and signatures of the non-equilibrium processes, both non-Maxwellian distributions and non-equilibrium ionization, in the solar transition region, corona, solar wind, and flares. Basic properties of the non-Maxwellian…

Magnetic fields are the primary driver of the plasma thermodynamics in the upper solar atmosphere, especially in the corona. However, magnetic field measurements in the solar corona are sporadic, thereby limiting us from the complete…

The first stars and quasars are known sources of hard ionizing radiation in the first billion years of the Universe. We examine the joint effects of X-rays and hard UV radiation from such first-light sources on the hydrogen and helium…

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…

We have studied the effect of time-dependent ionization and recombination processes on magnetic reconnection in the solar corona. Petschek-type steady reconnection, in which model the magnetic energy is mainly converted at the slow-mode…

Context. In a previous paper (Afify et al. 2024), we have investigated the stability threshold of the ion-ion acoustic instability (IIAI) in parameter regimes compatible with recent Parker Solar Probe (PSP, (Fox et al. 2016)) observations,…

The interaction of intense extreme ultraviolet (XUV) laser pulses ($\lambda=32\rm\,nm$, $I=10^{11-14}$\,W/cm$^2$) with small rare-gas clusters (Ar$_{147}$) is studied by quasi-classical molecular dynamics simulations. Our analysis supports…

The properties of solar flare plasma can be determined from the observation of optically thin lines. The emitting ion distribution determines the shape of the line, with an isothermal Maxwellian ion distribution producing a Gaussian…