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in creator/contributor: "Pearlstein, L. D."  
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Toward a design for the ITER plasma shape and stability control system

Description: A design strategy for an integrated shaping and stability control algorithm for ITER is described. This strategy exploits the natural multivariable nature of the system so that all poloidal field coils are used to simultaneously control all regulated plasma shape and position parameters. A nonrigid, flux-conserving linearized plasma response model is derived using a variational procedure analogous to the ideal MHD Extended Energy Principle. Initial results are presented for the non-rigid plasma… more
Date: July 1, 1994
Creator: Humphreys, D. A.; Leuer, J. A.; Kellman, A. G.; Haney, S. W.; Bulmer, R. H.; Pearlstein, L. D. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quantitative Tests of ELMs as Intermediate N Peeling-Ballooning Modes

Description: OAK A271 QUANTITATIVE TESTS OF ELMS AS INTERMEDIATE N PEELING-BALLOONING MODES. Two of the major issues crucial for the design of the next generation tokamak burning plasma devices are the predictability of the edge pedestal height and control of the divertor heat load in H-mode configurations. Both of these are strongly impacted by edge localized modes (ELMs) and their size. A working model for ELMs is that they are intermediate toroidal mode number, n {approx} 5-30, peeling-ballooning modes d… more
Date: July 1, 2002
Creator: Lao, L. L.; Snyder, P. B.; Leonard, A. W.; Osborne, T. H.; Petrie, T. W.; Ferron, J. R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Weakly relativistic modeling of refraction and absorption for waves with small N{sub {parallel}}

Description: Transmission measurements for waves near the fundamental and harmonics of the electron-cyclotron frequency indicate that propagation and absorption is not always correctly described when ray trajectories are obtained using cold-plasma analysis. Improved methods have been developed for evaluating the Shkarofsky functions, which appear in the weakly relativistic approximation of the dielectric tensor, for small parallel index of refraction. Computational results for vertical third-harmonic X-mode… more
Date: January 1, 1995
Creator: Smith, G. R.; Pearlstein, L. D. & Kritz, A. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Stable bootstrap-current driven equilibria for low aspect ratio tokamaks

Description: Low aspect ratio tokamaks can potentially provide a high ratio of plasma pressure to magnetic pressure {beta} and high plasma current I at a modest size, ultimately leading to a high power density compact fusion power plant. For the concept to be economically feasible, bootstrap current must be a major component of the plasma current. A high value of the Troyon factor {beta}{sub N} and strong shaping are required to allow simultaneous operation at high {beta} and high bootstrap current fraction… more
Date: August 1, 1996
Creator: Miller, R. L.; Lin-Liu, Y. R.; Turnbull, A. D.; Chan, V. S.; Pearlstein, L. D.; Sauter, O. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Current profile modeling to extend the duration of high performance advanced tokamak modes in DIII-D

Description: In DIII-D, as in a number of tokamaks, high performance is obtained with various optimized magnetic shear configurations that exhibit internal transport barriers. Negative central shear (NCS) discharges are created transiently during the current ramp-up by auxiliary heating and current drive from neutral beam injection. Both q{sub min} and the radius at which it occurs, {rho}{sub qmin}, decrease with time as the Ohmic current diffuses inward. The q-profiles calculated using EFIT with external m… more
Date: July 1, 1998
Creator: Casper, T. A.; Nevins, W. M.; Pearlstein, L. D.; Rice, B. W.; Stallard, B. W.; Hawreliak, J. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Advanced Tokamak Scenario Modeling with Off-Axix ECH in DIII-D

Description: Time-dependent simulations with transport coefficients derived from experimentally achieved discharges are used to explore the capability of off-axis electron cyclotron current drive (ECCD) to control hollow current profiles in negative central shear discharges. Assuming these transport coefficients remain unchanged at higher EC power levels, the simulation results show that high confinement, high normalized beta and high bootstrap fraction can be achieved with EC power expected to be available… more
Date: July 1, 1999
Creator: Murakami, M.; Casper, T. A.; Lao, L. L.; St. John, H. E.; Deboo, J. C.; Greenfield, C. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

DIII-D Quiescent Double Barrier Regime Experiments and Modeling

Description: Discharges characteristic of the quiescent double barrier (QDB) regime [1] are attractive for development of advanced tokamak (AT) scenarios relevant to fusion reactors [2] and they offer near term advantages for exploring and developing control techniques. We continue to explore the QDB regime in DIII-D to improve understanding of formation and control of these discharges and to explore scaling to steady-state reactors. The formation of an internal transport barrier (ITB) provides a naturally … more
Date: July 1, 2002
Creator: Casper, T. A.; Burrell, K. H.; DeBoo, J. C.; Doyle, E. J.; Gohil, P.; Greenfield, C. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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