Journal ArticleDOI
Electron impact ionization cross sections and rates for highly ionized atoms.
TLDR
In this paper, the authors presented a simple analytical form, based on a set of parameters derived from distorted wave exchange cross-section calculations, for hydrogen, helium, and lithium-like ions.Abstract:
Electron impact ionization cross sections and rates for hydrogen-, helium- and lithium-like ions are presented in simple analytical form, based on a set of parameters derived from distorted wave exchange cross section calculations. Isoelectronic fits to the parameters used in the formulate allow rapid generation of cross sections and rates for any ion in these sequences with a minimum of computational effort. The use of accurate Bethe slopes in the cross section-fitting algorithm yields good accuracy both in the near threshold and high energy regions. The rate coefficient is given in the form of a correction to the commonly used Seaton formula and is thus readily adaptable to existing plasma modeling computer codes. Comparisons of the present results with other theoretical and experimental data are made.read more
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Solar UV and X-ray spectral diagnostics
Giulio Del Zanna,Helen E. Mason +1 more
TL;DR: In this article, a review of the diagnostic methods used to measure electron densities, electron temperatures, differential emission measure (DEM), and relative chemical abundances is presented, focusing on the optically thin emission from the solar atmosphere, mostly found at UV and X-ray (XUV) wavelengths.
Journal ArticleDOI
Electron-Ion Recombination Rate Coefficients, Photoionization Cross Sections, and Ionization Fractions for Astrophysically Abundant Elements. II. Oxygen Ions
TL;DR: In this paper, a set of new atomic data for ionization balance in radi- atively and collisionally ionized astrophysical plasmas is presented, and a single set of total electron-ion recombination rate coefficients is thereby obtained as a function of electron temperature.
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A Unified Computational Model for Solar and Stellar Flares
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The optical spectrum of the sn 1006 supernova remnant revisited
Parviz Ghavamian,P. Frank Winkler,P. Frank Winkler,John C. Raymond,Knox S. Long,Knox S. Long +5 more
TL;DR: In this paper, the authors presented the deepest optical spectrum acquired to date of Balmer-dominated shocks in the northwest rim of SN 1006 and detected the broad and narrow components of Hα, Hβ, and Hγ and reported the first detection of the He I λ6678 emission line in this supernova remnant.
Journal ArticleDOI
A Unified Computational Model for Solar and Stellar Flares
TL;DR: In this article, the authors present a unified computational framework which can be used to describe impulsive flares on the Sun and on dMe stars, assuming that the flare impulsive phase is caused by a beam of charged particles that is accelerated in the corona and propagates downward depositing energy and momentum along the way.
References
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Journal ArticleDOI
Electron Impact Ionization Cross-Sections and Ionization Rate Coefficients for Atoms and Ions from Hydrogen to Calcium
TL;DR: In this paper, electron-impact ionization cross-sections for single ionization from the ground state are given for free atoms and for all ionization stages from hydrogen to calcium (Z=20).
Journal ArticleDOI
The spectrum of the solar corona
TL;DR: In this article, the interpretation of coronal observations in X-ray, ultra-violet visible and radio wavelengths is reviewed, and the authors present a survey of the results.
Journal ArticleDOI
Electron-impact ionization cross sections for highly ionized hydrogen- and lithiumlike atoms
TL;DR: In this article, the Coulomb-Born and distorted-wave approximations of the electron-impact ionization cross sections for highly ionized atoms in the hydrogen and lithium isoelectronic sequences have been computed in several variants of the CBE and distorted wave approximation.
Journal ArticleDOI
Collisions between electrons and ions
K T Dolder,B Peart +1 more
TL;DR: In this article, the authors discuss electron-ion collisions from an experimental viewpoint, with an emphasis on recent experiments and new techniques, such as ion traps and sequential mass spectrometry.
Journal ArticleDOI
Total cross sections for inelastic scattering of charged particles by atoms and molecules. v. evaluation to the next order beyond the bethe asymptote.
Yong-Ki Kim,Mitio Inokuti +1 more
TL;DR: In this article, the Bethe procedure was extended to include three constants instead of the usual two, and the Mott formula was used to estimate the correction for electron exchange in the ionization cross section.