Diagnostics of hot electrons leaving the ECR plasma sustained by the high-power gyrotron

Abstract

Energy distribution of electrons in the electron-cyclotron resonance (ECR) discharge has a complicated shape as a function of various parameters that still remains unknown. Meanwhile, it is an important plasma characteristic. There are some methods and approaches, which give the possibility to measure or estimate the properties of the distribution. One of them, similar to the ion mass spectrometry [1], was used in this work to obtain the energy distribution of electrons escaping the magnetic confinement in the non-classical continuous ECR ion source with high (up to 50–100 W/cm3) specific energy input along with bremsstrahlung spectra. A threshold-like behaviour was discovered, which comprised of the bursts of energetic electrons, bremsstrahlung and, supposedly, the development of kinetic instabilities, once the energy input exceeds a certain level.