Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma

Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q₀'' (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calc...

Ausführliche Beschreibung

Gespeichert in:

Bibliographische Detailangaben
Veröffentlicht in:	Physical review letters 2010-10, Vol.105 (14), p.145003-145003, Article 145003
Hauptverfasser:	Toi, K, Watanabe, F, Tokuzawa, T, Ida, K, Morita, S, Ido, T, Shimizu, A, Isobe, M, Ogawa, K, Spong, D A, Todo, Y, Watari, T, Ohdachi, S, Sakakibara, S, Yamamoto, S, Inagaki, S, Narihara, K, Osakabe, M, Nagaoka, K, Narushima, Y, Watanabe, K Y, Funaba, H, Goto, M, Ikeda, K, Ito, T, Kaneko, O, Kubo, S, Murakami, S, Minami, T, Miyazawa, J, Nagayama, Y, Nishiura, M, Oka, Y, Sakamoto, R, Shimozuma, T, Takeiri, Y, Tanaka, K, Tsumori, K, Yamada, I, Yoshinuma, M, Kawahata, K, Komori, A
Format:	Artikel
Sprache:	eng
Schlagworte:	70 PLASMA PHYSICS AND FUSION TECHNOLOGY ALFVEN WAVES CHARGED PARTICLES COUPLING FLUID MECHANICS HYDRODYNAMICS HYDROMAGNETIC WAVES IONS LAYERS MAGNETOHYDRODYNAMICS MECHANICS PLASMA PLASMA PRESSURE PRESSURE GRADIENTS REVERSED SHEAR SHEAR TAIL IONS VARIATIONS
Online-Zugang:	Volltext
Tags:	Tag hinzufügen Keine Tags, Fügen Sie den ersten Tag hinzu!

Beschreibung
Zusammenfassung:	Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q₀'' (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.
ISSN:	0031-9007 1079-7114
DOI:	10.1103/physrevlett.105.145003