Korovin V. Application of RF sources of electromagnetic fields in Uragane stelarators

This dissertation presents the results of experimental research of the developed RF sources intended for creation and heating of plasma by pulsed RF fields in Uragane toroidal installations. The study of the influence of plasma on the operation of the created high-power pulsed RF generators Kascade-1 and Kascade-2 is conducted. The results of the experimental study of RF cleaning of the vacuum chamber of stellarators carried out with the help of this equipment are presented. The result of studying the cleaning of a vacuum chamber by a continuous VHF discharge with the help of an improved source of electromagnetic field of the VHF range is presented. The possibility of using such a source, creating a continuous VHF discharge at a frequency above the cyclotron resonance for cleaning the vacuum chamber of the stelarator, has been experimentally confirmed. Measurements also confirm that the discharge is three-dimensional. To control the dynamics of vacuum chamber cleaning, a new method using a cryogenic trap has been developed, which allows to quickly control changes in the amount of pumped gas from the vacuum chamber. The results of studying the mode of preionization by an electric field in the frequency band 3 to 7 MHz in the vacuum chamber of the Uragane-3M stelarator using a developed and constructed RF source Kascade-0 loaded on a small loop antenna are presented. The use of this field allowed to create a preliminary preionization plasma. The creation of this plasma allowed the development of further discharge in a shorter and more constant period of time. It is developed a method of electron suppression escaped by creating an electric constant field. The influence of the suppression regime on the plasma parameters was investigated.