I=_IINCI'rIDN PI.A_WnRA I_"IYSiCIS NOTICE J This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liabili_ or responsibi!li;ty for the accuracy, completeness, or usefulness of any information,apparatus, product, or process disclosed,or represents that its use would not infd!nge privately owned

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... . Reference herein to any specific commercial produce, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily const_e or imply its endorsement, recommendation,or favoring by the United States Govemment or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Govemment or any agency thereof. PACS Nos. 52.35. Ra, 52.35.Bj, 52.25.Fi, 52.35.Hr "['he nortlinear dynamics of kinetic A_fvdn waves, resonantly excited by energetic ions/alpha particles, is investigated. It is shown that a-partic}es govern both linear instability and nonlinear saturation dynamics, while the background MHD turbulence results onl:_, in a nonlinear real frequency shift. The most efficient saturation mechanism is fotmd to be self-induced profile modification. Expressions for the fluctuation amplitudes and the c_-particle rad}al flux are sv}f-consistently derived. Tb_e work represents the first self-consistent, r,urbulent treatment of collective c_-partic[e Iosses by Alfvdnic fluctuations.