Theoretical description of discharge plasma and calculation of maximum output intensity of He-Ne waveguide lasers as a function of discharge tube radius

This paper deals with the properties of He-Ne waveguide lasers. An improved theory of the positive column is presented which assumes that at low currents, wall charges restrict the column to a narrow plasma channel and cause the electron temperature to rise. This theory is tested by comparison of measured and calculated current-voltage characteristics and shows good qualitative agreement. Taking into consideration the wall sheath at small currents, the output intensity is calculated. It turns out that an optimum tube radius,
R \approx 0.1
mm, exists at which the output intensity has its maximum.