1. The drift reversal capability in quasi-axisymmetric stellarators
- Author
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Yokoyama Masayuki, Okamura Shoichi, Matsuoka Keisuke, and Itoh Kimitaka
- Subjects
Physics ,Nuclear and High Energy Physics ,Condensed matter physics ,Turbulence ,Adiabatic invariance ,Rotational symmetry ,Magnetic confinement fusion ,Plasma ,Mechanics ,Condensed Matter Physics ,law.invention ,Magnetic field ,Controllability ,law ,Stellarator - Abstract
The drift reversal capability of trapped particles has been investigated in quasi-axisymmetric (QA) configurations for the confinement improvement as has been experimentally demonstrated in other axisymmetric configurations. The properties of J (second adiabatic invariance), its profile and maximum-J capability are examined for this purpose. Due to the non-axisymmetric nature of the magnetic field strength, a region of local maximum of J is created to cause the drift reversal. This region can be controlled radially and also toroidally with the introduction of symmetric breaking components of B, externally. The increase of magnetic shear in finite beta equilibria also has a favourable effect on the drift reversal. Thus, maximum-J capability and its external controllability are demonstrated for QA stellarators, by which the impact of magnetic configuration on turbulent transport can be studied.
- Published
- 2002
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