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Title: Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX

Abstract

Beam ion transport in the presence of low frequency MHD activity in National Spherical Tokamak Experiment (NSTX) plasma is modeled numerically and analyzed theoretically in order to understand basic underlying physical mechanisms responsible for the observed fast ion redistribution and losses. Numerical modeling of the beam ions flux into the NPA in NSTX shows that after the onset of low frequency MHD activity high energy part of beam ion distribution, E{sub b} > 40keV, is redistributed radially due to stochastic diffusion. Such diffusion is caused by high order harmonics of the transit frequency resonance overlap in the phase space. Large drift orbit radial width induces such high order resonances. Characteristic confinement time is deduced from the measured NPA energy spectrum and is typically {approx} 4msec. Considered MHD activity may induce losses on the order of 10% at the internal magnetic field perturbation {delta}B/B = {Omicron} (10{sup -3}), which is comparable to the prompt orbit losses.

Authors:
;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., Princeton, NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
828500
Report Number(s):
PPPL-3986
TRN: US0404006
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 16 Jul 2004
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFINEMENT TIME; DIFFUSION; DISTRIBUTION; HARMONICS; MAGNETIC FIELDS; PHASE SPACE; PLASMA; RESONANCE; SIMULATION; TRANSPORT; BEAM PLASMA INTERACTIONS; MAGNETOHYDRODYNAMICS (MHD); TOKAMAKS, NSTX

Citation Formats

N.N. Gorelenkov, and S.S. Medley. Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX. United States: N. p., 2004. Web. doi:10.2172/828500.
N.N. Gorelenkov, & S.S. Medley. Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX. United States. doi:10.2172/828500.
N.N. Gorelenkov, and S.S. Medley. Fri . "Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX". United States. doi:10.2172/828500. https://www.osti.gov/servlets/purl/828500.
@article{osti_828500,
title = {Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX},
author = {N.N. Gorelenkov and S.S. Medley},
abstractNote = {Beam ion transport in the presence of low frequency MHD activity in National Spherical Tokamak Experiment (NSTX) plasma is modeled numerically and analyzed theoretically in order to understand basic underlying physical mechanisms responsible for the observed fast ion redistribution and losses. Numerical modeling of the beam ions flux into the NPA in NSTX shows that after the onset of low frequency MHD activity high energy part of beam ion distribution, E{sub b} > 40keV, is redistributed radially due to stochastic diffusion. Such diffusion is caused by high order harmonics of the transit frequency resonance overlap in the phase space. Large drift orbit radial width induces such high order resonances. Characteristic confinement time is deduced from the measured NPA energy spectrum and is typically {approx} 4msec. Considered MHD activity may induce losses on the order of 10% at the internal magnetic field perturbation {delta}B/B = {Omicron} (10{sup -3}), which is comparable to the prompt orbit losses.},
doi = {10.2172/828500},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jul 16 00:00:00 EDT 2004},
month = {Fri Jul 16 00:00:00 EDT 2004}
}

Technical Report:

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