title: Effects of circulating energetic ions on sawtooth oscillations.
abstract: In contrast to the well-known result that the effects of the trapped energetic ions (TEI) on the internal kink mode are due to the toroidal precession of the TEI, it is found that the effects of the circulating energetic ions (CEI) on sawtooth are due to the toroidal circulation of the CEI. The effects of the CEI on sawtooth oscillations are found to be different from the well-known purely stabilizing effects of the TEI on sawtooth oscillations; the toroidal circulation of the co-CEI provides an additional sink of free energy and stabilizes the mode; the toroidal circulation of the counter-CEI provides an additional source of free energy and destabilizes the mode.
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031, China. sjwang@mail.ipp.ac.cn
authors.forename: Shaojie
authors.initials: S
authors.lastname: Wang
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ozeki
authors.forename: Kenji
authors.initials: K
authors.lastname: Tobita