Production of ECR Mirror Plasma by High Power Millimeter-Wave Radiation

Using a high power 60 GHz gyrotron, a high density electron cyclotron resonance (ECR) plasma production is studied in a simple mirror field in Ar gas, over the wide range of the gas pressures between 4×10-3 Pa and 2×10-1 Pa. Time variation of the electron density is studied in detail. In the quasi-steady state it reveals a fully ionized state with an electron density in the range of 1012 cm-3 at most, which is lower than the cut-off density of the incident wave whether the wave launch is performed in the radial or axial direction. Discussion of the usefulness of this plasma as a multiply-charged ion and UV-VUV radiation source is also given.