Impact of vibrationally and electronically excited H2 on the molecular assisted recombination rate in detached plasma regimes

Abstract

The vibrational redistribution of H2 molecules via the B1Σu+ and C1Πu states are included in the determination of molecular assisted recombination (MAR) rates and are found to have negligible impact in detached plasma regimes. In high recycling and detached divertor plasma conditions, MAR occurs through the higher levels (v≥4) of vibrationally excited H2 which are primarily populated through direct electron impact excitation or the electronic excitation of H2 molecules and the subsequent radiative decay to another vibrational state. We use the collisional-radiative model CRUMPET to evaluate MAR rate coefficients with electronic transitions included, which are applied to detached plasma parameters found in the linear plasma device Magnum-PSI.