Microwave-assisted modulation of light emission intensity in alkali-pyrotechnic plumes

Creating next-generation pyrotechnic emitters capable of dynamically controllable light output requires a paradigm shift away from emission control via formulation. This work demonstrates the ability to modulate intensity flame with 2.46 GHz microwave energy within multimodal cavity. Stoichiometric mixtures three systems are investigated: magnesium fuel oxidizers NaNO3, KNO3, or CsNO3. Using time-resolved visible and infrared spectroscopy high-speed color videography, illumination flames is found produce enhanced atomic photo alkali species. Emission increases up ~120% demonstrated, which predominantly in near-infrared wavelengths have little effect on chromaticity. At near- mid-IR wavelengths, gray body continuum enhancement observed moderate CO2 H2O bands. Sustained combustion products long after extinguishment was also demonstrated. A simplified model microwave-enhanced near-IR presented shown be consistent trend elevated for lower wavelength transitions. Sensitivity analysis performed suggests equilibrium population electronically excited atoms primarily responsible maximizing degree applied fields, especially extinguished low-temperature plumes. These findings suggest alkali-containing may useful strategy achieve dynamic intensity.