Collisional excitation and ionization of hydrogen by return current in solar flares

Free access article

Issue		A&A Volume 416, Number 3, March IV 2004


Page(s)		L13 - L16
Section		Letters
DOI		http://dx.doi.org/10.1051/0004-6361:20040034

A&A 416, L13-L16 (2004)
DOI: 10.1051/0004-6361:20040034

Letter

Collisional excitation and ionization of hydrogen by return current in solar flares

M. Karlický, J. Kasparová and P. Heinzel

Astronomical Institute of the Academy of Sciences of the Czech Republic, 25165 Ondrejov, Czech Republic
(Received 5 December 2003 / Accepted 30 January 2004)

Abstract
First a problem of the transport of electron beams with high energy fluxes into the cold chromosphere during the flare is presented. Then it is shown that the problem might be solved by the return current formed by superthermal (runaway) electrons. In such a case the return current electrons could influence hydrogen excitations and ionizations. Therefore, we computed collisional rates of such a return current and compared them with those of the thermal plasma and of a monoenergetic (10 keV) electron beam with the energy flux $F_{\rm E} = 10^{12}~\mbox{erg\,cm}^{-2}\,\mbox{ s}^{-1}$ penetrating into the flare atmosphere described by the F1 model (Machado et al. 1980). We show that in this situation the return current collisional rates can be dominant for some transitions.

Key words: Sun: flares -- plasmas -- atomic processes

Offprint request: M. Karlický, karlicky@asu.cas.cz

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.