Recommended data on proton-ion collision rate coefficients for Fe X–Fe XXIII ions

¹ National Institute for Fusion Science, Oroshi-cho, Toki, Gifu, 509-5292, Japan e-mail: murakami.izumi@nifs.ac.jp
² Joint Institute for High Temperatures of RAS, Izhorskaya 13/19, 125412 Russia e-mail: skobelev@ihed.ras.ru

Received: 27 April 2009
Accepted: 4 December 2009

Abstract

Aims. Proton-ion collisions are important for excitation or de-excitation of certain excited states in a high-temperature low density astrophysical plasma.

Methods. In the present work an evaluation of data obtained for proton-induced transitions in Fe X–Fe XXIII ions is carried out with the help of different theoretical methods.

Results. A simple analytical formula with seven parameters is suggested. This formula allows us to describe the dependence of the proton rate coefficient on the proton temperature in a wide temperature range. The values of the free parameters have been determined by fitting the approximation formula to numerical data and are presented for recommended data together with fitting accuracies. By comparing proton collision rates with electron rates it is shown that proton impact excitation processes may be important for Fe X, XI, XIII–XV, XVII–XXIII ions. The results obtained can be used for plasma kinetics calculations and for the development of spectroscopic methods of astrophysical plasma diagnostics.