Spatial thermal dose delivery in atmospheric pressure plasma jets

Atmospheric pressure plasma jets (APPJs) are increasingly used in plasma medicine and materials processing applications. Reproducible and effective operation of APPJs requires regulating the cumulative effects of plasma on a target substrate in the face of variabilities and exogenous disturbances. This article investigates spatial delivery of thermal effects - thermal dose - of plasma using a kHz-excited APPJ in helium translated over a dielectric substrate. A dose metric is presented for quantifying the cumulative, nonlinear thermal effects of plasma along the translation trajectory of the APPJ. An optimization-based feedback control strategy is proposed for real-time regulation of thermal dose delivery using spatial measurements of substrate temperature. Experimental investigation reveals that feedback control is crucial for achieving spatially uniform dose delivery.