(IC/1) Physics Issues in the Design of Low Aspect Ratio, High-Beta,
Quasi-Axisymmetric Stellarators
M. C. Zarnstorff1), L. A. Berry2),
A. H. Boozer3), A. Brooks1),
W. A. Cooper4), M. Drevlak5),
E. Fredrickson1), G. Y. Fu1),
R. Goldston1), R. Hatcher1),
S. Hirshman2), W. A. Houlberg2),
S. Hudson1), M. Isaev6), C. Kessel1),
L. P. Ku1), E. Lazarus2),
J. Lewandowski1), Z. Lin1), J. F. Lyon2),
R. Majeski1), P. Merkel5),
M. Mikhailov6), D. R. Mikkelsen1),
W. Miner7), D. Monticello1), H. Mynick1),
G. H. Neilson1), B. E. Nelson2),
C. Nührenberg5), N. Pomphrey1),
M. Redi1), W. Reiersen1), A. Reiman1),
P. Rutherford1), R. Sanchez8),
J. Schmidt1), D. A. Spong2), P. Strand2),
D. Strickler2), S. Subbotin6),
P. Valanju7), R. White1)
1) Princeton Plasma Physics Laboratory, Princeton,
NJ 08543 USA
2) Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
3) Columbia University, New York, NY 10027 USA
4) Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
5) Max Planck Institute for Plasma Physics, Greifswald, Germany
6) Kurchatov Institute, Moscow, Russia
7) University of Texas at Austin, Austin, TX 78712 USA
8) Universidad Carlos III de Madrid, Spain
Abstract. Compact stellarators have the potential to combine the best
features of the stellarator and the advanced tokamak, offering steady state
operation without current drive and potentially without disruptions at an
aspect ratio similar to tokamaks. A quasi-axisymmetric stellarator is
developed that is consistent with the bootstrap current and passively stable
to the ballooning, kink, Mercier, vertical, and neoclassical tearing modes
at
= 4.1% without need for conducting walls or external feedback.
The configuration has good flux surfaces and fast ion confinement. Thermal
transport analysis indicates that the confinement should be similar to
tokamaks of the same size, allowing access to the -limit with
moderate power. Coils have been designed to reproduce the physics
properties. Initial analysis indicates the coils have considerable
flexibility to manipulate the configuration properties. Simulations of the
current evolution indicate the kink-mode can remain stable during the
approach to high-beta.
IAEA 2001
