Neoclassical transport coefficients for finite-aspect-ratio and bean-shaped tokamak plasmas

1987 ◽  
Vol 30 (4) ◽  
pp. 1152 ◽  
Author(s):  
E. C. Crume ◽  
C. O. Beasley ◽  
S. P. Hirshman ◽  
W. I. van Rij
Keyword(s):  
Aspect Ratio ◽  
Transport Coefficients ◽  
Tokamak Plasmas ◽  
Neoclassical Transport

scholarly journals Aspect ratio scaling of ideal no-wall stability limits in high bootstrap fraction tokamak plasmas

2004 ◽  
Vol 11 (2) ◽  
pp. 639-646 ◽  
Author(s):  
J. E. Menard ◽  
M. G. Bell ◽  
R. E. Bell ◽  
D. A. Gates ◽  
S. M. Kaye ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Tokamak Plasmas ◽  
High Bootstrap ◽  
Stability Limits ◽  
Ratio Scaling

scholarly journals Natural poloidal asymmetry and neoclassical transport of impurities in tokamak plasmas

2019 ◽  
Vol 62 (2) ◽  
pp. 025001
Author(s):  
Patrick Maget ◽  
Judith Frank ◽  
Timothée Nicolas ◽  
Olivier Agullo ◽  
Xavier Garbet ◽  
...  
Keyword(s):  
Tokamak Plasmas ◽  
Neoclassical Transport

scholarly journals Electrostatic potential variations on stellarator magnetic surfaces in low collisionality regimes

2018 ◽  
Vol 84 (4) ◽  
Author(s):  
Iván Calvo ◽  
José Luis Velasco ◽  
Félix I. Parra ◽  
J. Arturo Alonso ◽  
José Manuel García-Regaña
Keyword(s):  
Aspect Ratio ◽  
Electrostatic Potential ◽  
Magnetic Surface ◽  
Radial Transport ◽  
Analytical Results ◽  
Magnetic Surfaces ◽  
Neoclassical Transport ◽  
Numerical Tools ◽  
Transport Problems ◽  
Computational Resources

The component of the neoclassical electrostatic potential that is non-constant on the magnetic surface, that we denote by$\tilde{\unicode[STIX]{x1D711}}$, can affect radial transport of highly charged impurities, and this has motivated its inclusion in some modern neoclassical codes. The number of neoclassical simulations in which$\tilde{\unicode[STIX]{x1D711}}$is calculated is still scarce, partly because they are usually demanding in terms of computational resources, especially at low collisionality. In this paper the size, the scaling with collisionality and with aspect ratio and the structure of$\tilde{\unicode[STIX]{x1D711}}$on the magnetic surface are analytically derived in the$1/\unicode[STIX]{x1D708}$,$\sqrt{\unicode[STIX]{x1D708}}$and superbanana-plateau regimes of stellarators close to omnigeneity; i.e. stellarators that have been optimized for neoclassical transport. It is found that the largest$\tilde{\unicode[STIX]{x1D711}}$that the neoclassical equations admit scales linearly with the inverse aspect ratio and with the size of the deviation from omnigeneity. Using a model for a perturbed omnigenous configuration, the analytical results are verified and illustrated with calculations by the codeKNOSOS. The techniques, results and numerical tools employed in this paper can be applied to neoclassical transport problems in tokamaks with broken axisymmetry.

Monte Carlo Simulation of Neoclassical Transport in Axisymmetric and Ripple Tokamaks

1982 ◽  
Vol 37 (8) ◽  
pp. 899-905 ◽  
Author(s):  
W. Lötz ◽  
J. Nührenberg
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Electric Field ◽  
Pitch Angle ◽  
Particle Distribution ◽  
Transport Coefficients ◽  
Angle Scattering ◽  
Wide Range ◽  
Neoclassical Transport

Simple axisymmetric and ripple tokamak model fields are used to compute neoclassical trans-port coefficients by Monte Carlo simulation over a wide range of mean free paths in the approximation of small gyroradius. Further assumptions are a monoenergetic particle distribution which is only subject to pitch angle scattering and a vanishing electric field. Pfirsch-Schlüter, plateau, banana and ripple transport coefficients are obtained. In the ripple regime the description is unified by introducing the concept of an effective ripple. Cases in which ripple transport is diminished due to collisionless detrapping are observed

Ideal MHD stability limits of low aspect ratio tokamak plasmas

1997 ◽  
Vol 37 (5) ◽  
pp. 595-610 ◽  
Author(s):  
J.E Menard ◽  
S.C Jardin ◽  
S.M Kaye ◽  
C.E Kessel ◽  
J Manickam
Keyword(s):  
Aspect Ratio ◽  
Tokamak Plasmas ◽  
Low Aspect Ratio ◽  
Ideal Mhd ◽  
Mhd Stability ◽  
Stability Limits
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