Two species drag/diffusion model for energetic particle driven modes

Journal Article · Tue Dec 19 00:00:00 EST 2017 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4996123· OSTI ID:1895306

Aslanyan, Valentin  ^[1]; Sharapov, S. E. ^[2]; Spong, D. A. ^[3]; Porkolab, M. ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2. Culham Science Centre, Abingdon (United Kingdom)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

A nonlinear bump-on-tail model for the growth and saturation of energetic particle driven plasma waves has been extended to include two populations of fast particles—one dominated by dynamical friction at the resonance and the other by velocity space diffusion. The resulting temporal evolution of the wave amplitude and frequency depends on the relative weight of the two populations. The two species model is applied to burning plasma with drag-dominated alpha particles and diffusion-dominated ICRH accelerated minority ions, showing the stabilization of bursting modes. Further, the model also suggests an explanation for the recent observations on the TJ-II stellarator, where Alfvén Eigenmodes transition between steady state and bursting as the magnetic configuration varied.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES); RCUK Energy Programme
• Grant/Contract Number: FG02-99ER54563; EP/P012450/1
• OSTI ID: 1895306
• Alternate ID(s): OSTI ID: 1414038
• Journal Information: Physics of Plasmas, Vol. 24, Issue 12; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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