Acceleration Characteristics of Ions Exhausted from Short Pulse Coaxial Laser-Assisted Pulse Plasma Thruster

Abstract

Characterization of temporal and spatial ion velocity distributions for a newly developed coaxial laser-assisted pulsed plasma thruster (LA-PPT) was conducted with a retarding potential analyzer (RPA). From the measurement, it was shown that the most probable velocities exhausted from the LA-PPT increased from 32 km/s to 47 km/s, and from 35 km/s to 51 km/s, for laser energies of 100 mJ and 150 mJ, respectively, with increase of charged voltages of capacitors from 0 V to 5 kV. In addition, It was shown that with a pulse discharge condition, a relatively flat part of ion beam distribution at the central region was observed roughly corresponding to a diameter of the thruster exit (30 mm), showing that ions emitted from the thruster were exhausted as a relatively straight beam without significantly diverging.