COMMENT: Comment on 'Particle charge evolution during acceleration processes in solar flares' by M D Rodríguez-Frías, L del Peral and J Pérez-Peraza

Abstract

Attention is drawn to the fact that results of the model obtained by Rodríguez-Frías et al are in conflict with both the straightforward physical consideration and the results of other models of charge-changing acceleration in solar flares. The numerical code given by Rodríguez-Frías et al generates an erroneous result that charge states of ions accelerated to few thermal energies can significantly differ from the equilibrium thermal ion charge state. However a straightforward calculation indicates that modification of the ion charge is possible only at much higher energies. We also provide a number of references to works on energy-dependent charge states of cosmic ray ions, which have been published for over 20 years, disproving a statement by Rodríguez-Frías et al that 'it is usually assumed that the charge state of cosmic rays corresponds to the ionization equilibrium of the plasma where they undergo acceleration'.