Low frequency sawtooth precursor activity in ASDEX Upgrade

Autor:	N. Lazanyi, L. Horvath, V. Igochine, M. Maraschek, Gergö Pokol, András Magyarkuti, Gabor Por, Gergely Papp
Přispěvatelé:	ASDEX Upgrade Team
Jazyk:	angličtina
Rok vydání:	2011
Předmět:	Physics Tokamak Mode (statistics) Sawtooth wave Plasma Low frequency Condensed Matter Physics law.invention Nuclear Energy and Engineering Orders of magnitude (time) ASDEX Upgrade law Harmonics Atomic physics
Zdroj:	Plasma Physics and Controlled Fusion, v.53 (2011) Plasma Physics and Controlled Fusion
Popis:	This paper describes the precursor activity observed in the ASDEX Upgrade tokamak before sawtooth crashes in various neutral beam heated plasmas, utilizing the soft x-ray diagnostic. In addition to the well-known (m, n) = (1,1) internal kink mode and its harmonics, a lower frequency mode is studied in detail. Power modulation of this mode is found to correlate with the power modulation of the (1, 1) kink mode in the quasistationary intervals indicating possible nonlinear interaction. Throughout the studied sawtooth crashes, the power of the lower frequency mode rose by several orders of magnitude just before the crash. In addition to its temporal behaviour, its spatial structure was estimated and the most likely value was found to be (1, 1). A possible role of this mode in the mechanism of the sawtooth crash is discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bb6320c79364b45452104139bff59b3b http://edoc.mpg.de/517057 Zobrazit plný text záznamu