Magnetic-Field-Dependent Breakdown of CO2-Laser-Produced Plasma

Abstract

The threshold pressure for breakdown of helium and argon gas by 10.6‐μm radiation from a TEA CO₂ laser is strongly depressed by a steady magnetic field parallel to the direction of propagation of the laser beam. At 87 kOe, the zero‐field threshold pressure is reduced from 166 to 96 Torr in helium and from 66 to 21 Torr in argon. This result can be explained semiquantitatively by a simple model of breakdown that takes into account the inhibition of radial electron diffusion by the magnetic field.