Trials of RF plasma production using different antenna geometries with magnetic field

Plasma production studies excited by the radio frequency (RF) wave were car ried out using various antenna configurations. Six types of side antennae, located outside the large cylindrical chamber, and two types of internal lo op antennae were tested. The ion saturation current Ii, of a probe and the plasma emission were measured as a function of the filling pressure, the RF power and the magnetic field. With the increase in the power and the magne tic field, Ii, increased in most cases, while some of the antennae showed t he maximum ii, values under low magnetic field. Among the side antennae, a spiral antenna produced the highest value of ii, in a wide operational wind ow. For the case of the internal loop antennae, the electric field parallel to the magnetic field did not show a significant contribution to plasma pr oduction. These results suggest the importance of the loop-like RF-induced electric held. When an external magnetic field was applied, the uniformity of the plasma produced by the internal loop antennae in both the radial and axial directions was improved.