Energetic particle transport in compact quasi-axisymmetric stellarators

Energetic particle transport in compact quasi-axisymmetric stellarators

Robustness and Flexibility in Compact Quasiaxial Stellarators: Global Ideal MHD Stability and Energetic Particle Transport

Neoclassical Transport in Quasi-Axially Symmetric Stellarators

We present a numerical and analytic assessment of the transport in two quasi-axially symmetric stellarators, including one variant of the MHH2 class[l] of such devices, and a configuration we refer t o as NHH2, closely related t o MHH2. Monte Carlo simulation results are compared with expectations from established stellarator neoclassical theory, and with some empirical stellarator scalings, us...

Resilience of quasi-isodynamic stellarators against trapped-particle instabilities.

It is shown that in perfectly quasi-isodynamic stellarators, trapped particles with a bounce frequency much higher than the frequency of the instability are stabilizing in the electrostatic and collisionless limit. The collisionless trapped-particle instability is therefore stable as well as the ordinary electron-density-gradient-driven trapped-electron mode. This result follows from the energy...

Density Gontrol Problems in Large Stellarators with Neoclassical Particle TransPort

With respect to the particle flux, the off-diagonal term in the neoclassical transport matrix becomes crucial in the stellarator long-mean-free-path (lmfp) regime. Central heating with peaked temperature profiles can make an active density profile control by central particle refuelling mandatory. The neoclassical particle confinement can exceed significantly the energy confinement at the outer ...