The two leading concepts for confining high-temperature fusion plasmas are the tokamak
and the stellarator. Tokamaks are rotationally symmetric and use a large plasma current to …

Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good
confinement with plasma parameters relevant to a future stellarator power plant. Plasma …

A significant improvement of plasma parameters in the optimized stellarator W7-X is found
after injections of frozen hydrogen pellets. The ion temperature in the post-pellet phase …

An overview is given of physics differences between stellarators and tokamaks, including
magnetohydrodynamic equilibrium, stability, fast-ion physics, plasma rotation, neoclassical …

The neoclassical confinement and the bootstrap current are analysed in the configuration
space of W7-X by self-consistent neoclassical transport simulations. Since the establishment …

The neoclassical transport optimization of the Wendelstein 7-X stellarator has not resulted in
the predicted high energy confinement of gas fueled electron-cyclotron-resonance-heated …

Stellarator magnetic configurations need to be optimized in order to meet all the required
properties of a fusion reactor. In this work, it is shown that a flat-mirror quasi-isodynamic (QI) …

A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-
particle losses and is stable to ideal magnetohydrodynamic (MHD) instabilities. The design …

In this work, we examine the validity of several common simplifying assumptions used in
numerical neoclassical calculations for nonaxisymmetric plasmas, both by using a new …

Abstract Wendelstein 7-X (W7-X) is currently under commissioning in preparation for its
initial plasma operation phase, operation phase 1.1 (OP1. 1). This first phase serves …