Email this article Onset condition of the subcritical geodesic acoustic mode instability in the presence of energetic-particle-driven geodesic acoustic mode
- Authors: Itoh K.1,2, Itoh S.2,3, Kosuga Y.3,4, Lesur M.3, Ido T.1
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Affiliations:
- National Institute for Fusion Science
- Research Center for Plasma Turbulence
- Research Institute for Applied Mechanics
- Institute for Advanced Study
- Issue: Vol 42, No 5 (2016)
- Pages: 418-423
- Section: Waves and Instabilities in Plasma
- URL: https://journals.rcsi.science/1063-780X/article/view/185710
- DOI: https://doi.org/10.1134/S1063780X16050056
- ID: 185710
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Abstract
An analytic model is developed for understanding the abrupt onset of geodesic acoustic mode (GAM) in the presence of chirping energetic-particle-driven GAM (EGAM). This abrupt excitation phenomenon has been observed on LHD plasma. Threshold conditions for the onset of abrupt growth of GAM are derived, and the period doubling phenomenon is explained. The phase relation between the mother mode (EGAM) and the daughter mode (GAM) is also discussed. This result contributes to the understanding of “trigger problems” of laboratory and nature plasmas.
About the authors
K. Itoh
National Institute for Fusion Science; Research Center for Plasma Turbulence
Author for correspondence.
Email: itoh@nifs.ac.jp
Japan, Toki; Kasuga
S.-I. Itoh
Research Center for Plasma Turbulence; Research Institute for Applied Mechanics
Email: itoh@nifs.ac.jp
Japan, Kasuga; Kasuga
Y. Kosuga
Research Institute for Applied Mechanics; Institute for Advanced Study
Email: itoh@nifs.ac.jp
Japan, Kasuga; Fukuoka
M. Lesur
Research Institute for Applied Mechanics
Email: itoh@nifs.ac.jp
Japan, Kasuga
T. Ido
National Institute for Fusion Science
Email: itoh@nifs.ac.jp
Japan, Toki
