Resonant Laser Ignition Study of HAN-HEHN Propellant Mixture

Abstract

Resonant laser ignition at wavelengths in the UV and IR was demonstrated for hydroxyl ammonium nitrate (HAN)–hydroxyethylhydrazinium nitrate (HEHN) mixtures. This prototypical ionic liquid propellant was successfully and reliably ignited under confinement with single laser pulses in the mid IR at 2.94 and 10.6 µm. UV wavelengths at 193 and 248 nm were also resonant with sample absorption, but they did not lead to ignition with the available excimer laser pulse energies. The results are consistent with absorption of the IR laser pulse within a short path length, efficient V→T relaxation, and thermal decomposition of HAN that leads to additional chemical reaction and ignition of milligram samples within tens of microseconds.