Detection of anisotropy in the electron velocity distribution produced by electron cyclotron resonance heating using the polarization of helium atom emission lines

摘要

The anisotropy in the electron velocity distribution (EVD) was measured using the polarization of two helium atom emission lines, 2(1)P-3(1)D (668 nm) and 2(3)P-3(3)D (588 nm), in a helium electron cyclotron resonance (ECR) discharge plasma. A small polarization degree of less than 4% was measured by adopting a temporal modulation technique. It was found that the polarization originated locally from around the ECR layer and that the anisotropic component of the EVD produced by ECR heating had an average kinetic energy of approximately 40 eV. Published by AIP Publishing.