ECR heating on the WEGA stellarator

• Дата: 2005
• Автори: Podoba, Y., Horvath, K., Laqua, H.P., Lingertat, J., Otte, M., Wagner, F., Holzhauer, E.
• Формат: Стаття
• Мова: English
• Опубліковано: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2005
• Назва видання: Вопросы атомной науки и техники
• Теми: Magnetic confinement
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/79336
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: ECR heating on the WEGA stellarator / Y. Podoba, K. Horvath, H.P. Laqua, J. Lingertat, M. Otte, F. Wagner, E. Holzhauer // Вопросы атомной науки и техники. — 2005. — № 2. — С. 29-31. — Бібліогр.: 4 назв. — англ.

The plasma in the WEGA stellarator is generated and heated by Electron Cyclotron Resonance Heating (ECRH). The microwave is emitted from the low field side mid-plane with power of up to 6+20 kW and with a frequency of 2.45GHz (λ=12.45 cm). The low cut-off density of ncutoff=7.5×10¹⁶m⁻³ makes ECRH on the WEGA stellarator inefficient in both O-mode and X-mode regime. This was confirmed in the first experimental campaign by perpendicular launch of the microwave with a TE11 antenna. In these experiments only edge heating was observed. Density and temperature profiles were hollow [1]. For the over dense plasma heating, mode conversion into the electrostatic electron Bernstein waves (EBW) is required. Two schemes have been tested: the direct X-B (X-mode to Bernstein mode) conversion, where an X-wave must be launched perpendicular to the magnetic field into an over dense plasma with a steep density gradient. In these experiments the strong reflection of the microwave power at the cut-off layer prohibited efficient plasma heating. Another possibility is the O-X-B conversion scheme [2]. The methods of its achievement with different antennas are the subject of this paper.