Параметры публикации

Тип публикации: 

Статья в журнале/сборнике


Chirping instabilities produced by a runaway electron beam at a spherical tokamak





Наименование источника: 

  • Plasma Science and Technology

Обозначение и номер тома: 

Vol. 25, N. 7


  • Hefei, China


  • Hefei Institutes of Physical Science, Chinese Academy of Sciences and IOP Publishing

Год издания: 



Two different types of MHD instabilities with rapidly chirping frequency were found to arise in the Globus-M2 spherical tokamak in substantially different frequency ranges. The first type arises at frequencies of an order of 1 MHz in ohmic plasmas at relatively low density $\langle {n}_{{\rm{e}}}\rangle \lt 2\times {10}^{19}{\,{\rm{m}}}^{-3}$ in a wide range of toroidal magnetic fields and plasma currents. This type of instability was identified as compressional Alfvén waves, driven by electrons, accelerated during a sawtooth crush. It was found that the mode frequency is sweeping in time, according to the Berk–Breizman hole–clump nonlinear chirping model. The second type of wave arises in a specific single-swing regime of the central solenoid current with a very narrow plasma column, when the plasma tends to decay at extremely low density $\langle {n}_{{\rm{e}}}\rangle \lt 2\times {10}^{18}{\,{\rm{m}}}^{-3}$ and, in fact, is an instability of the runaway electron beam. The exited modes cover the whole observed frequency range and are divided into several (two or three) frequency regions: approximately 0–30 MHz, 60–120 MHz and sometimes 30–60 MHz. Reconnection of the branches was also observed. Single chirps are more rapid than for 1 MHz Alfvén instability and follow an exponential law. This paper, to our knowledge, is the first report of frequency chirping instabilities excited by accelerated electrons at a spherical tokamak.

Библиографическая ссылка: 

Балаченков И.М., Бахарев Н.Н., Гусев В.К., Ильясова М.В., Хилькевич Е.М., Коренев П.С., Коньков А.Е., Минаев В.Б., Митришкин Ю.В., Патров М.И., Петров Ю.В., Сахаров Н.В., Шевелев А.Е., Скрекель О.М. Chirping instabilities produced by a runaway electron beam at a spherical tokamak // Plasma Science and Technology. 2023. Vol. 25, N. 7. С. https://iopscience.iop.org/article/10.1088/2058-6272/acb875/meta.