First Observation of Alpha Particle Loss Induced by Kinetic Ballooning Modes in TFTR DT Experiments
Authors: Zuoyang Chang, R. V. Budny, L. Chen, D. Darrow, E. D. Fredrickson, A. Janos, D. Mansfield, E. Mazzucato, K. M. McGuire, R. Nazikian, G. Rewoldt, J. D. Strachan, W. M. Tang, G. Taylor, R. B. White, S. Zweben and the TFTR group
A correlation between the measured alpha particle loss and high frequency (~100-200 kHz) modes has been observed in some high b (=plasma pressure/magnetic pressure) DT plasmas in TFTR. These modes are localized around the peak plasma pressure gradient and have ballooning characteristics. An enhancement of 30% in the alpha particle loss correlated with a bursting mode and a factor of 2 enhancement correlated with multiple modes are observed. Linear instability analysis and particle simulation show that the plasma is unstable to the kinetic MHD ballooning modes and the loss is due to wave-particle resonances.