Plasma and Fusion Research
Volume 4, 014 (2009)
Rapid Communications
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan
- 1)
- National Institute for Fusion Science, Toki 509-5292, Japan
- 2)
- Graduate School of Frontier Science, The University of Tokyo, Kashiwa 277-8561, Japan
Abstract
An extension of geodesic acoustic mode (GAM) spectroscopy [Plasma Phys. Control. Fusion 49, L7 (2007)] is proposed. The ratio between the lowest frequency of the co-existing ion acoustic mode (IAM) and the frequency of GAM enables us to identify the safety factor of toroidal plasmas. The lowest frequency can be detected by bispectrum analysis when both GAM and IAM are excited. The possibility of measuring the safety factor is discussed.
Keywords
geodesic acoustic mode, ion acoustic mode, toroidal plasma, safety factor, new diagnostics, bicoherence
Full Text
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This paper may be cited as follows:
Sanae-I. ITOH, Seiya NISHIMURA, Kimitaka ITOH, Akihide FUJISAWA, Yoshihiko NAGASHIMA and Shigeru INAGAKI, Plasma Fusion Res. 4, 014 (2009).