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Title: Phase space effects on fast ion distribution function modeling in tokamaks

Integrated simulations of tokamak discharges typically rely on classical physics to model energetic particle (EP) dynamics. However, there are numerous cases in which energetic particles can suffer additional transport that is not classical in nature. Examples include transport by applied 3D magnetic perturbations and, more notably, by plasma instabilities. Focusing on the effects of instabilities, ad-hoc models can empirically reproduce increased transport, but the choice of transport coefficients is usually somehow arbitrary. New approaches based on physics-based reduced models are being developed to address those issues in a simplified way, while retaining a more correct treatment of resonant wave-particle interactions. The kick model implemented in the tokamak transport code TRANSP is an example of such reduced models. It includes modifications of the EP distribution by instabilities in real and velocity space, retaining correlations between transport in energy and space typical of resonant EP transport. The relevance of EP phase space modifications by instabilities is first discussed in terms of predicted fast ion distribution. Results are compared with those from a simple, ad-hoc diffusive model. It is then shown that the phase-space resolved model can also provide additional insight into important issues such as internal consistency of the simulations and modemore » stability through the analysis of the power exchanged between energetic particles and the instabilities. « less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
DOE Contract Number:
AC02-09CH11466
Product Type:
Dataset
Research Org(s):
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Resource Relation:
Related Information: Physics of Plasmas, Vol. 23, p. 056106 (2016)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Integrated modeling energetic particle distribution energetic particle transport kick model TRANSP NUBEAM
Related Identifiers:
OSTI Identifier:
1366480

White, R. B., Podesta, M., Gorelenkova, M., Fredrickson, E. D., and Gorelenkov, N. N.. Phase space effects on fast ion distribution function modeling in tokamaks. United States: N. p., Web. doi:10.11578/1366480.
White, R. B., Podesta, M., Gorelenkova, M., Fredrickson, E. D., & Gorelenkov, N. N.. Phase space effects on fast ion distribution function modeling in tokamaks. United States. doi:10.11578/1366480.
White, R. B., Podesta, M., Gorelenkova, M., Fredrickson, E. D., and Gorelenkov, N. N.. 2016. "Phase space effects on fast ion distribution function modeling in tokamaks". United States. doi:10.11578/1366480. https://www.osti.gov/servlets/purl/1366480.
@misc{osti_1366480,
title = {Phase space effects on fast ion distribution function modeling in tokamaks},
author = {White, R. B. and Podesta, M. and Gorelenkova, M. and Fredrickson, E. D. and Gorelenkov, N. N.},
abstractNote = {Integrated simulations of tokamak discharges typically rely on classical physics to model energetic particle (EP) dynamics. However, there are numerous cases in which energetic particles can suffer additional transport that is not classical in nature. Examples include transport by applied 3D magnetic perturbations and, more notably, by plasma instabilities. Focusing on the effects of instabilities, ad-hoc models can empirically reproduce increased transport, but the choice of transport coefficients is usually somehow arbitrary. New approaches based on physics-based reduced models are being developed to address those issues in a simplified way, while retaining a more correct treatment of resonant wave-particle interactions. The kick model implemented in the tokamak transport code TRANSP is an example of such reduced models. It includes modifications of the EP distribution by instabilities in real and velocity space, retaining correlations between transport in energy and space typical of resonant EP transport. The relevance of EP phase space modifications by instabilities is first discussed in terms of predicted fast ion distribution. Results are compared with those from a simple, ad-hoc diffusive model. It is then shown that the phase-space resolved model can also provide additional insight into important issues such as internal consistency of the simulations and mode stability through the analysis of the power exchanged between energetic particles and the instabilities.},
doi = {10.11578/1366480},
year = {2016},
month = {6} }
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