Feedback effects between resonance surface and space harmonics of external perturbations in tokamak

• Дата: 2005
• Автори: Semenov, I.B., Mirnov, S.V., Fredrickson, E.D., Voznesensky, V.A.
• 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/123456789/79310
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Feedback effects between resonance surface and space harmonics of external perturbations in tokamak / I.B. Semenov, S.V. Mirnov, E.D. Fredrickson, V.A. Voznesensky // Вопросы атомной науки и техники. — 2005. — № 2. — С. 11-13. — Бібліогр.: 15 назв. — англ.

Resonant magnetic surfaces in a tokamak can amplify the spatial harmonics of external perturbations, which may come from other resonant surfaces, from error fields, or from a feedback system. The behavior of this active resonant media can be roughly approximated with a system of coupled Van der Pole oscillators. The effect of frequency injection locking (or spatial harmonics injection locking in the plasma frame) is typical for these nonlinear systems. It happens when the amplitude of one modes increases and this mode becomes a dominant mode. Transition into synchronized condition can occur in a time scale of ~ 50 -100 µsec. For a tokamak it means that the stability of a large scale MHD perturbation can change jumpily, because frequency (phase) lock may create a positive feedback between resonant surfaces (or between resonant surfaces and the external feedback system). This effect probably determines the explosive dynamic of the disruptive instability.