HV discharge acceleration by sequences of UV laser filaments with visible and near-infrared pulses

TL;DR

This study demonstrates that UV laser filaments can effectively trigger and guide high-voltage discharges over 37 cm, with additional visible and near-infrared pulses enhancing discharge speed by heating the plasma channel.

Contribution

It introduces a method using UV laser filaments combined with visible and near-infrared pulses to accelerate high-voltage discharges, highlighting the effects of plasma heating and photodetachment.

Findings

UV filaments reduce breakdown electric field by half

Discharge probability reaches 80% at 920 kV/m

Adding IR pulses doubles the discharge acceleration

Abstract

We investigate the triggering and guiding of DC high-voltage discharges over a distance of 37 cm by filaments produced by ultraviolet (266 nm) laser pulses of 200 ps duration. The latter reduce the breakdown electric field by half and allow up to 80% discharge probability in an electric field of 920 kV/m. This high efficiency is not further increased by adding nanosecond pulses in the Joule range at 532 nm and 1064 nm. However, the latter statistically increases the guiding length, thereby accelerating the discharge by a factor of 2. This effect is due both to photodetachment and to the heating of the plasma channel, that increases the efficiency of avalanche ionization and reduces electron attachment and recombination.