Polar pattern of ion-plasma beams formed in vacuum flashover of inclined surface of polymer in the field of a plane capacitor

Development of pulsed plasma thrusters raise the question of the mechanism of particle acceleration in the process of surface breakdown. One possible mechanism is the acceleration of ions during the Coulomb explosion of micro-clusters of the decomposition products of the dielectric under the influence of a powerful electrical pulse. The paper presents the radiation pattern of the particle beam formed by the flashover on the dielectric surface in near-uniform electric field. Voltage pulses with amplitude up to 140 kV and duration of 50 ns were applied to the samples. Dielectric surface and electric field vector E formed an angle of 30 degrees. We measured the velocity of the particles formed beam, the time delay from the supply voltage until the breakdown. Shows photographs of the breakdown channel with a marked complex structure. Dependence of the average mass of the particle velocity on the angle between the surface and the vector E were produced. It is shown that the preferential direction of propagation of the beam particles matches with the normal to the surface of an insulator and does not depend on its orientation relative to the electrodes, which confirms the assumption that the acceleration of particles in the plasma layer formed during the breakdown on a dielectric surface.