Speaker
Mr
Alexander Solomakhin
(Budker Institute of Nuclear Physics)
Description
This paper summarizes the results of experiments on electron cyclotron emission (ECE) measurements at the axially symmetric magnetic mirror device gas dynamic trap GDT (Budker Institute, Novosibirsk). The new ECE diagnostics has been installed to facilitate the successful ECRH experiment and operates in the vicinity of the ECRH frequency (54.5 GHz). The particulars of plasma EC emission were studied experimentally in a broad range of discharge scenarios in GDT. Measured thermal spectra have validated the existing physical conceptions about the EC resonance heating of plasma in the machine, in particular the significance of the auxiliary ECR surface in the launching port that affects the wave propagation in core plasma. Efficiency of the dedicated non-planar magnetic coil for the suppression of the auxiliary resonance have been validated with the thermal ECE measurements. Measured non-thermal ECE spectra have unambiguously confirmed the existence of suprathermal electrons in GDT for the first time. As it turned out, these electrons are generated by the intense microwave field both during the ECR start-up (breakdown) stage and during the ECR heating of the main plasma. Time dependence of ECE level corresponding to variation of confining magnetic field allowed to reconstruct distribution function of suprathermal electron and estimate their population.
The work is supported by the Russian Science Foundation (project No 14-12-01007).
Primary author
Mr
Alexander Solomakhin
(Budker Institute of Nuclear Physics)
Co-authors
Prof.
Alexander Shalashov
(Institute of Applied Physics RAS)
Mr
Dmitry Yakovlev
(Budker Institute of Nuclear Physics)
Dr
Egor Gospodchikov
(Institute of Applied Physics RAS)
Dr
Lev Lubyako
(Institute of Applied Physics RAS)
Dr
Peter Bagryansky
(Budker Institute of Nuclear Physics)
