Enhancement of Plasma Density in an Arc Discharge

Abstract

The amplification or generation of coherent signals by electron‐beam—plasma interactions requires the creation of a high‐density stable plasma. A plasma density of approximately 1015 particles∕cm3 is required to produce a plasma resonance frequency of 300 Gc∕sec. The density in an arc‐discharge plasma has been increased using mechanical and magnetic constriction methods with the result that np=7.5×1014 particles∕cm3 is realized at a discharge current of 4 A in argon. Double Langmuir probe measurements on density and temperature in the plasma are presented and interpreted for zero and finite magnetic‐field conditions