(526d) Microwave Enhancement of Energetic Materials Combustion

The development of a new class of smart energetic materials with on-command controllable performance is essential to meeting future energetic material mission needs. In previous work, we have shown that alkali earth metal doping of an ammonium perchlorate composite propellant can enable strong electromagnetic flame coupling, leading to enhancement of flame structure (flame temperature), and ~70% increase in atmospheric burning rate due to the formation of microwave-supported plasmas within propellant flames. In this overview presentation, we report on the use of 1 kW, 2.45 GHz RF energy interaction with a variety of propellant and pyrotechnic energetic materials within an impedance matched, tuned waveguide cavity. We specifically discuss the use of alternative alkali dopants with improved (lower) ionization energies for use in further improving gas phase enhancement of compositions as RF-condensed phase considerations in gas phase enhancement as well as techniques to engineer the condensed phase of pyrotechnic formulations to enable switchable burning rates through RF-mediated reconfiguration of condensed phase constituents. For these techniques, we study the enhancements to burning rate, flame temperature, and emission using high speed video, two-color high speed video pyrometry, and UV-VIS-IR spectroscopy, respectively.