The structure of detonation waves in supernovae

Abstract

The theory of gaseous detonation is applied to thermonuclear detonation waves in supernovae. First, the two-temperature structure of strong shock waves in a dense degenerate plasma is considered. The ion-electron energy transfer rate is calculated for a plasma with arbitrary degeneracy of electrons. It is shown that the non-equilibrium heating of ions is unimportant for detonation. The steady planar one-dimensional structure of detonation waves both in C + O mixtures and in pure helium 4He is computed for densities from 106 to 3 × 109 g cm−3. The thickness of the detonation waves is obtained as a function of the initial density of the matter. The self-sustained detonation of helium is a Chapman–Jouguet detonation at all the densities considered. The self-sustained detonation of C + O mixtures is a Chapman–Jouguet detonation only at densities less than ∼ 107 g cm−3. At higher densities it is a pathological detonation with some velocity |$D^\ast \gt D_\text{CJ}$|⁠. Products of detonation are Fe-peak nuclei if the NSE state occurs in a detonated matter. The products are the intermediate mass nuclei Si, S, Ca, etc. in the case of incomplete detonation of C + O mixtures. The products are the partially unburned helium and Fe-peak nuclei with extremely small fractions of intermediate mass nuclei in the case of incomplete detonation of 4He. The thickness of detonation waves in C + O mixtures differs appreciably from that in helium.