Speakers
Prof.
Alexander Shalashov
(Institute of Applied Physics RAS)
Mr
Dmitry Yakovlev
(Budker INP SB RAS)
Description
A new discharge startup scenario has been developed for the Gas Dynamic Trap (GDT) magnetic mirror experiment. The primary neutral beam injection (NBI) plasma heating system requires a sufficiently dense plasma target with a degree of ionization, which is compatible with accumulation of fast ions. In the reported experiments, instead of the conventional axial plasma injection, a high-frequency radiation is used to produce such a target directly in the central cell. One of the microwave beams generated by GDT`s electron cyclotron resonance heating (ECRH) system is used to ionize a portion of neutral gas, which is admitted to vacuum vessel. The ECR absorption of incident power supports further ionization and eventually builds up a plasma target suitable for NBI capture. With application of the NBI a steady accumulation of fast ions is observed, resulting in a discharge with aggregate fast ion energy, plasma temperature and other parameters similar to the conventional regime with the arc plasma gun. The particulars of discharge scenario and experimental data on plasma evolution during ECR heating are reported, along with the dependencies on incident microwave power, magnetic configuration and the initial pressure of neutral gas. The characteristics of high-power NBI discharge are described and differences to the conventional scenario are discussed. Experimental data is compared to theoretical models of microwave breakdown in a mirror trap.
The work is supported by the Russian Science Foundation (project No 14-12-01007).
Primary author
Mr
Dmitry Yakovlev
(Budker INP SB RAS)
Co-authors
Prof.
Alexander Shalashov
(Institute of Applied Physics RAS)
Mr
Alexander Solomakhin
(Budker INP SB RAS)
Dr
Egor Gospodchikov
(Institute of Applied Physics RAS)
Dr
Peter Bagryansky
(Budker INP SB RAS)
