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in creator/contributor: "Solomon, W M"  
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Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas

Description: In tokamak plasmas with low levels of toroidal rotation, the radial electric fi eld Er is a combination of pressure gradient and toroidal and poloidal rotation components, all having similar magnitudes. In order to assess the validity of neoclassical poloidal rotation theory for determining the poloidal rotation contribution to Er , Dα emission from neutral beam heated tokamak discharges in DIII-D [J.L. Luxon, Nucl. Fusion 42 , 614 (2002)] has been evaluated in a sequence of low torque (electro… more
Date: May 10, 2013
Creator: Grierson, B. A.; Burrell, K. H.; Solomon, W. M.; Budny, R. V. & Candy, J.
Partner: UNT Libraries Government Documents Department
open access

Momentum Transport Studies in High E x B Shear Plasmas in NSTX

Description: Experiments have been conducted on NSTX to study both steady state and perturbative mo mentum transport. These studies are unique in their parameter space under investigation, where the low aspect ratio of NSTX results in rapid plasma rotation with E x B shearing rates high enough to suppress low-k turbulence. In some cases, the ratio of momentum to energy confinement time is found to exceed five. Momentum pinch velocities of order 10-40 m/s are inferred from the measured angular momentum flux … more
Date: June 26, 2008
Creator: Solomon, W M; Bell, R E; LeBlanc, B P; Menard, J E; Rewoldt, G; Wang, W et al.
Partner: UNT Libraries Government Documents Department
open access

Extraction of Poloidal Velocity from Charge Exchange Recombination Spectroscopy Measurements

Description: A novel approach has been implemented on DIII-D to allow the correct determination of the plasma poloidal velocity from charge exchange spectroscopy measurements. Unlike usual techniques, the need for detailed atomic physics calculations to properly interpret the results is alleviated. Instead, the needed atomic physics corrections are self-consistently determined directly from the measurements, by making use of specially chosen viewing chords. Modeling results are presented that were used to d… more
Date: July 16, 2004
Creator: Solomon, W. M.; Burrell, K. H.; Gohil, P.; Groebner, R. J. & Baylor, L. R.
Partner: UNT Libraries Government Documents Department
open access

Observation of Energetic Particle Driven Modes Relevant to Advanced Tokamak Regimes

Description: Measurements of high-frequency oscillations in JET [Joint European Torus], JT-60U, Alcator C-Mod, DIII-D, and TFTR [Tokamak Fusion Test Reactor] plasmas are contributing to a new understanding of fast ion-driven instabilities relevant to Advanced Tokamak (AT) regimes. A model based on the transition from a cylindrical-like frequency-chirping mode to the Toroidal Alfven Eigenmode (TAE) has successfully encompassed many of the characteristics seen in experiments. In a surprising development, the … more
Date: October 21, 2004
Creator: Nazikian, R.; Alper, B.; Berk, H. L.; Borba, D.; Boswell, C.; Budny, R. V. et al.
Partner: UNT Libraries Government Documents Department
open access

Cross-calibrating Spatial Positions of Light-viewing Diagnostics using Plasma Edge Sweeps in DIII-D

Description: An experimental technique is presented that permits diagnostics viewing light from the plasma edge to be spatially calibrated relative to one another. By sweeping the plasma edge, each chord of each diagnostic sweeps out a portion of the light emission profile. A nonlinear least-squares fit to such data provides superior cross-calibration of diagnostics located at different toroidal locations compared with simple surveying. Another advantage of the technique is that it can be used to monitor th… more
Date: July 7, 2003
Creator: Solomon, W.M.; Burrell, K.H.; Gohil, P.; Groebner, R. & Kaplan, D.
Partner: UNT Libraries Government Documents Department
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