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Registration Number

0225U004261, (0124U004306) , R & D reports

Title

Critical issues for stellarators as thermonuclear installations

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Проведення основних експериментів та основний аналіз результатів

Head

Moiseienko Volodymyr Ye., Доктор фізико-математичних наук

Registration Date

27-11-2025

Organization

National Science Center "Kharkiv Institute of Physics and Technology"

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Radio frequency creation of plasma on the U-2M stellarator. Research on the glow discharge and recommendations for the use of this discharge on stellarators, in particular on W7-X. Improvement of refraction-based microwave diagnostics methods for studying plasma at the U-2M stellarator. Modeling of plasma equilibrium and retention, MHD activity of U-2M discharges with a small field and high plasma beta. Comparative analysis of MHD and, in particular, Alphen modes on stellarators and tokamaks.

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For the glow discharge, the dependences of the breakdown voltage on the pressure of Ar, He and H2 were measured. It was established that the geometry of the anodes significantly affects the breakdown voltage.The current-voltage characteristics of the glow discharge in the toroidal vacuum chamber U-2M in various gases were measured. The optical spectra of the glow discharge plasma in the atmosphere of argon, helium and hydrogen were analyzed. The spectral lines of excited atoms (molecules) and ions (atomic and molecular) in the glow discharge plasma were identified. The microwave diagnostic methods based on microwave refraction were adapted for U-2M. The VMEC code was adapted for the Uragan-2M stellarator for calculations in the ideal approximation at the previous stage of the project. The data adapted for use by the VMEC code allowed it to calculate the plasma equilibrium with a free boundary. The practical use of this code allowed modeling the effect of plasma current and plasma pressure on the energy and particle confinement in the Uragan-2M stellarator during the current stage of the project. A comparison of the parameters of the Alfvén eigenmodes in stellarators and tokamaks was carried out. Various eigenmodes were studied in the W7-X stellarator and the TCV and MAST-U tokamaks. The rotational transformation profile and, in particular, the magnetic shear profile are crucial parameters for the stability of the dominant modes. In contrast to the strongly varying rotational transformation angle profile of the tokamak, this profile is flat in the TJ-II stellarator and especially flat in the optimized W7-X stellarator. A small perturbation of this profile due to the additional plasma current can lead to the excitation of Alfvén eigenmodes in stellarators, in particular, the excitation of such modes as reverse shear Alfvén modes (RSAE) and global Alfvén modes (GAE).

Product Description

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Yurii V. Kovtun
Valerii B. KOROVIN
Volodymyr Y. Moiseenko
Mykola B. Dreval
Leonid Y. Konotopskyi
Yurii P. MARTSENIUK
Andrii S. PAHUR

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2025-11-27