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

The vibrational redistribution of H₂ molecules via the B¹Σ_u⁺ and C¹Π_u 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.