PPPL-4022 is available in pdf format (628 KB).

Non-conventional Fishbone Instabilities

Authors: Ya.I. Kolesnichenko, V.V. Lutsenko, V.S. Marchenko, and R.B. White

Date of PPPL Report: November 2004

Presented at: the 20th IAEA Fusion Energy Conference, 1-6 November 2004, Vilamoura, Portugal. The papers will be published by the IAEA as unedited proceedings in electronic format on CD-ROM and on the IAEA Physics Section web site as soon as possible after the conference.

New instabilities of fishbone type are predicted. First, a trapped-particle-induced m = n = 1 instability with the mode structure having nothing to do with the conventional rigid kink displacement. This instability takes place when the magnetic field is weak, so that the precession frequency of the energetic ions is not small as compared to the frequency of the corresponding Alfvén continuum at r = 0 and the magnetic shear is small inside the q = 1 radius [the case relevant to spherical tori]. Second, an Energertic Particle Mode fishbone instability driven by circulating particles. Third, a double-kink-mode instability driven by the circulating energetic ions. In particular, the latter can have two frequencies simultaneously: we refer to it as "doublet" fishbones. This instability can occur when the radial profile of the energetic ions has an off-axis maximum inside the region of the mode localization.