A quasi-isodynamic configuration with good confinement of fast ions at low plasma β

Nuclear Fushion

article

E. Sánchez¹  J.L. Velasco¹  I. Calvo¹  S. Mulas¹ 

[1] Laboratorio Nacional de Fusión

关键词: stellarator;    optimization;    magnetic confinement;    quasi-isodynamic;    fast-ion confinement;    optimized coils;   

DOI  :  10.1088/1741-4326/accd82

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

A new quasi-isodynamic (QI) stellarator configuration optimized for the confinement of energetic ions at low plasmaβis obtained. The numerical optimization is carried out using the STELLOPT suite of codes. New proxies to measure closeness to quasi-isodynamicity and quality of fast ion confinement have been included. The new configuration has poloidally closed contours of magnetic field strength, low magnetic shear and a rotational transform profile allowing an island divertor. It shows ideal and ballooning magnetohydrodynamic stability up to beta = 5% , reduced effective ripple, with epsilon_mathrm{eff}lt 0.5%in the plasma core. Even at lowβ , the configuration approximately satisfies the maximum- Jproperty, and the confinement of fast ions is good at betasim1.5%and becomes excellent at reactor values, betasim 4% . An evaluation of theD ₃₁ neoclassical mono-energetic coefficient supports the expectation of a reduced bootstrap current for plasmas confined in QI configurations. A set of filamentary coils that preserve the good confinement of fast ions in the core is presented.

【 授权许可】

Unknown