A Description of the Full Particle Orbit Following SPIRAL Code for Simulating Fast-ion Experiments in Tokamaaks
Authors: G.J. Kramer, R.V. Budny, A. Bortolon, E.D. Fredrickson1, G.Y. Fu,W.W. Heidbrink, R. Nazikian, E. Valeo, and M.A. Van Zeeland
Abstract:
The numerical methods used in the full particle-orbit following SPIRAL code are described and a
number of physics studies performed with the code are presented to illustrate its capabilities. The
SPIRAL code is a test-particle code and is a powerful numerical tool to interpret and plan fast-ion
experiments in Tokamaks. Gyro-orbit effects are important for fast ions in low-field machines such
as NSTX and to a lesser extent in DIII-D. A number of physics studies are interlaced between the
description of the code to illustrate its capabilities. Results on heat loads generated by a localized
error-field on the DIII-D wall are compared to measurements. The enhanced Triton losses caused
by the same localized error-field are calculated and compared to measured neutron signals. MHD
activity such as tearing modes and Toroidicity-induced Alfv´en Eigenmodes (TAEs) have a profound
effect on the fast-ion content of Tokamak plasmas and SPIRAL can calculate the effects of MHD
activity on the confined and lost fast-ion population as illustrated for a burst of TAE activity in
NSTX. The interaction between Ion Cyclotron Range of Frequency (ICRF) heating and fast ions
depends solely on the gyro-motion of the fast ions and is captured exactly in the SPIRAL code. A
calculation of ICRF absorption on beam ions in ITER is presented. The effects of high harmonic
fast wave heating on the beam-ion slowing-down distribution in NSTX is also studied.
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Submitted to: Plasma Physics and Controlled Fusion (June 2012)
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Download PPPL-4788 (pdf 12 MB 44 pp)
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