3.1. Measurement setup for discharge arcs

As shown in Figure 3, a ns-pulsed Nd:YAG laser (InnoLas Corp. SpitLight 600, wavelength: 1064 nm, pulse energy: ~600 mJ, pulse width: 7 ns) is used for laser ablation of propellants. The laser pulse is irradiated into a vacuum chamber (vacuum degree: <5.0 <sup>10</sup><sup>4</sup> Pa) through a quartz window and focused on the propellant with a focusing lens (f = 400 mm). The thruster is ignited and initiated by the ns-pulsed laser. Discharge arcs formed between the electrodes of thruster. The discharge current is monitored with a current monitor (Rogowski Coil, CWT150, sensitivity: 0.2 mV/A, maximum current: 30.0 kA) and a digital oscilloscope (Tektronix DPO 4340). The discharge voltage between the electrodes is measured using a standard high-voltage probe (Tektronix P5100).
