Recent advances in charged particle energy deposition and applications to supernova spectra

Abstract

Most studies of charged particle energy deposition deal with the stopping of particles by the medium. Predicting the excitation of the medium by the particles has received much less attention. The key to the solution of this latter problem is the assembly of a realistic set of detailed atomic cross sections (DACS) for all important inelastic processes induced by electrons with energies varying from the incident electron energy down to the lowest inelastic threshold. Two methods of assembling such sets are described; one based upon experimental generalized oscillator strengths, the second based upon quantum mechanical calculations using an atomic independent particle model. Next we describe a continuous slowing down approximation (CSDA) method of utilizing these cross sections for calculating the excitation of a medium by incident electrons. We also describe the yield spectra method based upon a modified discrete energy bin technique which allows for the discrete nature of the slowing down process. In addition, we describe a method of spatial‐yield spectra calculated by Monte Carlo techniques which gives the spatial patterns of various excitations. Finally, we discuss the possibility of applying these recent techniques to the prediction of late time SN I spectra, using the radioactive excitation source model.