Kinetic treatment of hypersonic plasmas during re-entry*

A prominent application of Hypersonics is the re-entry of spacecraft vehicles in the atmosphere. During re-entry, thermal plasma is created by shock compression of the gas between the bow shock front and the surface of the vehicle. The electron kinetics of such plasmas is modeled by solving the time-dependent electron Boltzmann equation for the electron energy distribution function. The energy source for the electrons is elastic and second-kind collisions from vibrationally excited states of N₂. Numerical simulations of air plasma showed that the electron energy distribution function deviates from Maxwellian and the collisional rates differ by orders of magnitude from those computed with a Maxwellian distribution.