Electron fishbones: Theory and experimental evidence
Abstract
We discuss the processes underlying the excitation of fishbone-like internal kink instabilities driven by supra-thermal electrons generated experimentally by different means: Electron Cyclotron Resonance Heating (ECRH) and by Lower Hybrid (LH) power injection. The peculiarity and interest of exciting these electron fishbones by ECRH only or by LH only is also analyzed. Not only the mode stability is explained, but also the transition between steady state nonlinear oscillations to bursting (almost regular) pulsations, as observed in FTU, is interpreted in terms of the LH power input. These results are directly relevant to the investigation of trapped alpha particle interactions with low-frequency MHD modes in burning plasmas: in fact, alpha particles in reactor relevant conditions are characterized by small dimensionless orbits, similarly to electrons; the trapped particle bounce averaged dynamics, meanwhile, depends on energy and not mass.
Keywords
Cite
@article{arxiv.0707.2852,
title = {Electron fishbones: Theory and experimental evidence},
author = {F. Zonca and P. Buratti and A. Cardinali and L. Chen and J. -Q. Dong and Y. -X. Long and A. V. Milovanov and F. Romanelli and P. Smeulders and L. Wang and Z. -T. Wang and C. Castaldo and R. Cesario and E. Giovannozzi and M. Marinucci and V. Pericoli Ridolfini},
journal= {arXiv preprint arXiv:0707.2852},
year = {2009}
}
Comments
28 pages 8 figures