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Stellarator bootstrap current and plasma flow velocity at low collisionality

Part of: Focus on Fusion

Published online by Cambridge University Press:  23 March 2017

P. Helander ,
F. I. Parra  and
S. L. Newton
P. Helander*
Affiliation:
Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
F. I. Parra
Affiliation:
Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, UK Culham Centre for Fusion Energy, Culham Science Centre, Oxon OX14 3DB, UK
S. L. Newton
Affiliation:
Culham Centre for Fusion Energy, Culham Science Centre, Oxon OX14 3DB, UK Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
*
†Email address for correspondence: per.helander@ipp.mpg.de
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Abstract

The bootstrap current and flow velocity of a low-collisionality stellarator plasma are calculated. As far as possible, the analysis is carried out in a uniform way across all low-collisionality regimes in general stellarator geometry, assuming only that the confinement is good enough that the plasma is approximately in local thermodynamic equilibrium. It is found that conventional expressions for the ion flow speed and bootstrap current in the low-collisionality limit are accurate only in the $1/\unicode[STIX]{x1D708}$-collisionality regime and need to be modified in the $\sqrt{\unicode[STIX]{x1D708}}$-regime. The correction due to finite collisionality is also discussed and is found to scale as $\unicode[STIX]{x1D708}^{2/5}$.

Keywords

fusion plasmaplasma confinementplasma flows
Type
Research Article
Information
Journal of Plasma Physics , Volume 83 , Issue 2 , April 2017 , 905830206
Copyright
© Cambridge University Press 2017 

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