Nanosecond time-resolved 2 + 2 Radar REMPI measurements performed in molecular nitrogen

Many molecular interactions associated with combustion, high speed gas physics and plasma processes involve dynamics associated with molecular non-equilibrium phenomena. Radar REMPI (Resonance-Enhanced Multi-Photon Ionization) is a potential method for measuring local, time accurate non-equilibrium conditions. It uses multi-photon ionization to generate electrons and ions from selected atomic or molecular states. The ionization is resonantly enhanced when the multi-photon progression passes through an intermediate state. Thus, REMPI is state and species specific. Radar REMPI detects the ionization by microwave scattering and provides a remote, non-intrusive means of probing a physical system. This work is focused upon using Radar REMPI to measure population distributions in molecular nitrogen. Current measurements, made under equilibrium conditions, agree well with model predictions. Future work will focus on optimizing the accuracy of the diagnostic and probing a rotational and/or vibrational non-equilibrium environment.

Nanosecond time-resolved 2 + 2 Radar REMPI measurements performed in molecular nitrogen Conference Paper