Design of a Quasi-Axisymmetric Stellarator
Abstract
We have been pursuing the design of a stellarator with the following properties: 1) magnetic field sufficiently close to quasi-axisymmetric that the neoclassical transport is small compared to the turbulent transport; 2) adequate ideal MHD stability β limit; 3) good equilibrium flux surfaces at β values of interest; 4) aspect ratio comparable to that of tokamaks. For our equilibrium and stability β limits, the goal is to exceed 5%. Equilibrium flux surfaces and magnetic island widths are evaluated using the PIES 3D equilibrium code. The assumed current profile corresponds to the self-consistent bootstrap current. Analytic estimates suggest that neoclassical currents will have a large effect on island widths, leading to the requirement that the ι profile be monotonically increasing. One option being considered for construction of the stellarator would be to use the present PBX toroidal field coils and vacuum vessel, building additional coils inside the vacuum vessel. Fifteen MW of neutral beam power are available, allowing a test of the β limit.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1997
- Bibcode:
- 1997APS..DPPhTP114R