Micrometer-Resolution High Speed Imaging of Pulsed Microdischarge Ignition

The application of a short, pulsed excitation is known to allow for higher power deposition into microdischarges without the onset of instabilities. Here, a MOSFET-based high voltage pulser is used to drive a 50-torr argon microdischarge with short pulsed currents of ~75 A, with <;100-ns full-width at half-maximum, and a repetition rate of 1 MHz. With this excitation, an average power density of ~10¹³ W/m³ is achieved, with a peak power density~3.10¹⁴ W/m³. A high speed iCCD camera is used to observe ignition processes and confirm the absence of unstable operation. The images were taken using a 5-ns gate time with a spatial resolution of ~2.5 μm.