Investigation of ECR plasma uniformity from the point of view of production and confinement

Abstract

To clarify the production mechanism of a high-density uniform electron cyclotron resonance (ECR) plasma, the spatial wave patterns of electromagnetic waves in the plasma were measured by the interferometric method under several experimental conditions and compared with the power absorption profiles indicated by simulation. It was experimentally shown that the refraction of the right circularly polarized wave (the R wave) corresponds to the spatial profile of the plasma density. On the other hand, the simulation showed the correlation between the wave refraction and power absorption, which implies that the power transportation depending upon the refraction of the R wave has a great influence on ECR plasma uniformity. Furthermore, it was found that the plasma uniformity was improved by applying permanent magnets, and the maximum electron density in the case of the uniform plasma is approximately 2×10 11 cm −3. The ion temperature in the Ar plasma decreases from 0.17 to 0.06 eV in the presence of the permanent magnets.