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Title: Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport

Abstract

Concerns about the flexibility and robustness of a compact quasiaxial stellarator design are addressed by studying the effects of varied pressure and rotational transform profiles on expected performance. For thirty, related, fully three-dimensional configurations the global, ideal magnetohydrodynamic (MHD) stability and energetic particle transport are evaluated. It is found that tokamak intuition is relevant to understanding the magnetohydrodynamic stability, with pressure gradient driving terms and shear stabilization controlling both the periodicity preserving, N=0, and the nonperiodicity preserving, N=1, unstable kink modes. Global kink modes are generated by steeply peaked pressure profiles near the half radius and edge localized kink modes are found for plasmas with steep pressure profiles at the edge as well as with edge rotational transform above 0.5. Energetic particle transport is not strongly dependent on these changes of pressure and current (or rotational transform) profiles, although a weak inverse dependence on pressure peaking through the corresponding Shafranov shift is found. While good transport and MHD stability are not anticorrelated in these equilibria, stability only results from a delicate balance of the pressure and shear stabilization forces. A range of interesting MHD behaviors is found for this large set of equilibria, exhibiting similar particle transport properties. (c) 2000more » American Institute of Physics.« less

Authors:
 [1];  [2];  [3];  [1];  [4];  [5];  [5];  [5]
  1. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
  2. University of Montana, Missoula, Montana 59801 (United States)
  3. Centre de Recherche des Physique des Plasmas, Lausanne, (Switzerland)
  4. Max Planck Institut fuer Plasma Physik, Greifswald, (Germany)
  5. Princeton Plasma Physies Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
Publication Date:
OSTI Identifier:
20216543
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 7; Journal Issue: 6; Other Information: PBD: Jun 2000; Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CHARGED-PARTICLE TRANSPORT; STELLARATORS; MAGNETOHYDRODYNAMICS; PLASMA INSTABILITY; MHD EQUILIBRIUM; KINK INSTABILITY; KINETIC EQUATIONS; PLASMA PRESSURE; PLASMA CONFINEMENT; MAGNETIC CONFINEMENT; THEORETICAL DATA

Citation Formats

Redi, M. H., Diallo, A., Cooper, W. A., Fu, G. Y., Nuehrenberg, C., Pomphrey, N., Reiman, A. H., and Zarnstorff, M. C. Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport. United States: N. p., 2000. Web. doi:10.1063/1.874090.
Redi, M. H., Diallo, A., Cooper, W. A., Fu, G. Y., Nuehrenberg, C., Pomphrey, N., Reiman, A. H., & Zarnstorff, M. C. Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport. United States. doi:10.1063/1.874090.
Redi, M. H., Diallo, A., Cooper, W. A., Fu, G. Y., Nuehrenberg, C., Pomphrey, N., Reiman, A. H., and Zarnstorff, M. C. Thu . "Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport". United States. doi:10.1063/1.874090.
@article{osti_20216543,
title = {Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport},
author = {Redi, M. H. and Diallo, A. and Cooper, W. A. and Fu, G. Y. and Nuehrenberg, C. and Pomphrey, N. and Reiman, A. H. and Zarnstorff, M. C.},
abstractNote = {Concerns about the flexibility and robustness of a compact quasiaxial stellarator design are addressed by studying the effects of varied pressure and rotational transform profiles on expected performance. For thirty, related, fully three-dimensional configurations the global, ideal magnetohydrodynamic (MHD) stability and energetic particle transport are evaluated. It is found that tokamak intuition is relevant to understanding the magnetohydrodynamic stability, with pressure gradient driving terms and shear stabilization controlling both the periodicity preserving, N=0, and the nonperiodicity preserving, N=1, unstable kink modes. Global kink modes are generated by steeply peaked pressure profiles near the half radius and edge localized kink modes are found for plasmas with steep pressure profiles at the edge as well as with edge rotational transform above 0.5. Energetic particle transport is not strongly dependent on these changes of pressure and current (or rotational transform) profiles, although a weak inverse dependence on pressure peaking through the corresponding Shafranov shift is found. While good transport and MHD stability are not anticorrelated in these equilibria, stability only results from a delicate balance of the pressure and shear stabilization forces. A range of interesting MHD behaviors is found for this large set of equilibria, exhibiting similar particle transport properties. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.874090},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 6,
volume = 7,
place = {United States},
year = {2000},
month = {6}
}