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Title: Numerical Study of Instabilities Driven by Energetic Neutral Beam Ions in NSTX

Abstract

Recent experimental observations from NSTX [National Spherical Torus Experiment] suggest that many modes in a subcyclotron frequency range are excited during neutral-beam injection (NBI). These modes have been identified as Compressional Alfven Eigenmodes (CAEs) and Global Alfven Eigenmodes (GAEs), which are driven unstable through the Doppler-shifted cyclotron resonance with the beam ions. The injection velocities of the NBI ions in NSTX are large compared to Alfven velocity, V(sub)0 > 3V(sub)A, and a strong anisotropy in the fast-ion pitch-angle distribution provides the energy source for the instabilities. Recent interest in the excitation of Alfven Eigenmodes in the frequency range omega less than or approximately equal to omega(sub)ci, where omega(sub)ci is the ion cyclotron frequency, is related to the possibility that these modes can provide a mechanism for direct energy transfer from super-Alfvenic beam ions to thermal ions. Numerical simulations are required in order to find a self-consistent mode structure, and to include the effects of finite-Larmor radius (FLR), the nonlinear effects, and the thermal plasma kinetic effects.

Authors:
; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
814697
Report Number(s):
PPPL-3832
TRN: US0304316
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 7 Jul 2003
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANISOTROPY; CYCLOTRON FREQUENCY; CYCLOTRON RESONANCE; DISTRIBUTION; ENERGY SOURCES; ENERGY TRANSFER; EXCITATION; FREQUENCY RANGE; INCLINATION; KINETICS; PLASMA; VELOCITY; ALFVeN WAVES; NUMERICAL SIMULATION; WAVE INTERACTION-PARTICLES

Citation Formats

E.V. Belova, N.N. Gorelenkov, C.Z. Cheng, and E.D. Fredrickson. Numerical Study of Instabilities Driven by Energetic Neutral Beam Ions in NSTX. United States: N. p., 2003. Web. doi:10.2172/814697.
E.V. Belova, N.N. Gorelenkov, C.Z. Cheng, & E.D. Fredrickson. Numerical Study of Instabilities Driven by Energetic Neutral Beam Ions in NSTX. United States. doi:10.2172/814697.
E.V. Belova, N.N. Gorelenkov, C.Z. Cheng, and E.D. Fredrickson. Mon . "Numerical Study of Instabilities Driven by Energetic Neutral Beam Ions in NSTX". United States. doi:10.2172/814697. https://www.osti.gov/servlets/purl/814697.
@article{osti_814697,
title = {Numerical Study of Instabilities Driven by Energetic Neutral Beam Ions in NSTX},
author = {E.V. Belova and N.N. Gorelenkov and C.Z. Cheng and E.D. Fredrickson},
abstractNote = {Recent experimental observations from NSTX [National Spherical Torus Experiment] suggest that many modes in a subcyclotron frequency range are excited during neutral-beam injection (NBI). These modes have been identified as Compressional Alfven Eigenmodes (CAEs) and Global Alfven Eigenmodes (GAEs), which are driven unstable through the Doppler-shifted cyclotron resonance with the beam ions. The injection velocities of the NBI ions in NSTX are large compared to Alfven velocity, V(sub)0 > 3V(sub)A, and a strong anisotropy in the fast-ion pitch-angle distribution provides the energy source for the instabilities. Recent interest in the excitation of Alfven Eigenmodes in the frequency range omega less than or approximately equal to omega(sub)ci, where omega(sub)ci is the ion cyclotron frequency, is related to the possibility that these modes can provide a mechanism for direct energy transfer from super-Alfvenic beam ions to thermal ions. Numerical simulations are required in order to find a self-consistent mode structure, and to include the effects of finite-Larmor radius (FLR), the nonlinear effects, and the thermal plasma kinetic effects.},
doi = {10.2172/814697},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jul 07 00:00:00 EDT 2003},
month = {Mon Jul 07 00:00:00 EDT 2003}
}

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