| IT08 · Self-consistent Study of Fast Particle Redistribution by Alfvén Eigenmodes
During Ion Cyclotron Resonance Heating
T. Bergkvist, T. Hellsten and T. Johnson
Alfvén Laboratory, Association Euratom-VR, Sweden
Abstract: Alfvén eigenmodes (AEs) excited by fusion born α particles can degrade the heating efficiency of a
burning plasma and throw out αs. To experimentally study the effects of excitation of AEs and the redistribution
of the fast ions, ion cyclotron resonance heating (ICRH) is often used. The distribution function of thermonuclear
αs in a reactor is expected to be isotropic and constantly renewed through DT reactions. The distribution function
of cyclotron heated ions is strongly anisotropic, and the ICRH do not only renew the distribution function but also
provide a strong decorrelation mechanism between the fast ions and the AE. Because of the sensitivity of the AE
dynamics on the details of the distribution function, the location of the resonance surfaces in phase space and the
extent of the overlapping resonant regions for different AEs, a self-consistent treatment of the AE excitation and
the ICRH is necessary. Interactions of fast ions with AEs during ICRH has been implemented in the SELFO code.
Simulations are in good agreement with the experimentally observer pitch-fork splitting and rapid damping of the
AE as ICRH is turned off. The redistribution of fast ions have been studied in the presence of several driven AEs.
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Synopsis (pdf)