Dynamics of an atmospheric pressure plasma plume generated by submicrosecond voltage pulses

TLDR

Nonequilibrium plasmas driven by sub‑microsecond high‑voltage pulses generate high‑energy electrons that enhance ionization and excitation. We present a device capable of launching a cold plasma plume into surrounding air. The plasma pencil, powered by few‑hundred‑nanosecond pulses at kilohertz rates, employs a photoionization model to explain the rapid propagation of its plasma bullet under low electric fields. Current‑voltage measurements and fast‑frame imaging confirm that the plume is a small, bullet‑like plasma volume moving at unusually high velocities.

Abstract

Nonequilibrium plasmas driven by submicrosecond high voltage pulses have been proven to produce high-energy electrons, which in turn lead to enhanced ionization and excitations. Here, we describe a device capable of launching a cold plasma plume in the surrounding air. This device, “the plasma pencil,” is driven by few hundred nanosecond wide pulses at repetition rates of a few kilohertz. Correlation between current-voltage characteristics and fast photography shows that the plasma plume is in fact a small bulletlike volume of plasma traveling at unusually high velocities. A model based on photoionization is used to explain the propagation kinetics of the plasma bullet under low electric field conditions.