z-logo
open-access-imgOpen Access
Characterization of Fast Ion Absorption of the High Harmonic Fast Wave in the National Spherical Torus Experiment
Author(s) -
A. Rosenberg,
J. Ménard,
J. R. Wilson,
S. Medle,
C. K. Phillips,
R. André,
D. S. Darro,
R. Dümont,
B.P. LeBlanc,
M. H. Redi,
T. K. Mau,
E. F. Jaeger,
P. M. Ryan,
D. W. Swain,
R. W. Harvey,
J. Egedal,
the NSTX Team
Publication year - 2003
Language(s) - English
Resource type - Reports
DOI - 10.2172/814742
Subject(s) - atomic physics , population , ion , neutron , absorption (acoustics) , torus , physics , computational physics , optics , nuclear physics , demography , geometry , mathematics , quantum mechanics , sociology
Ion absorption of the high harmonic fast wave in a spherical torus is of critical importance to assessing the viability of the wave as a means of heating and driving current. Analysis of recent National Spherical Torus Experiment (NSTX) shots has revealed that under some conditions when neutral beam and radio-frequency (RF) power are injected into the plasma simultaneously, a fast ion population with energy above the beam injection energy is sustained by the wave. In agreement with modeling, these experiments find the RF-induced fast ion tail strength and neutron rate at lower B-fields to be less enhanced, likely due to a larger beta profile, which promotes greater off-axis absorption where the fast ion population is small. Ion loss codes find the increased loss fraction with decreased B insufficient to account for the changes in tail strength, providing further evidence that this is an RF interaction effect. Though greater ion absorption is predicted with lower k(sub)||, surprisingly little variation in the tail was observed, along with a small neutron rate enhancement with higher k(sub)||. Data from the neutral particle analyzer, neutron detectors, X-ray crystal spectrometer, and Thomson scattering is presented, along with results from the TRANSP transport analysis code, ray-tracing codes HPRT and CURRAY, full-wave code and AORSA, quasi-linear code CQL3D, and ion loss codes EIGOL and CONBEAM

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here