Overdense plasma heating in Wendelstein 7-X(W7-X) stellarator

A New Dispersion Interferometer for the Stellarator Wendelstein 7-X

The construction of the Wendelstein 7-X stellarator

The construction status of the large superconducting stellarator Wendelstein 7-X is reported. The manufacturing and tests of the main components are reviewed and major design tasks during the device assembly phase are summarized. The assembly is currently proceeding on three out of five assembly stands. Four out of ten magnet half-modules are completed. Major work packages are the electric and ...

Spatial distribution of turbulence in the Wendelstein 7-AS stellarator

In this paper measurements of short wavelength electron density fluctuations using collective scattering of infrared light are presented. The Wendelstein 7-AS (W7-AS) stellarator (Renner H et al 1989 Plasma Phys. Control. Fusion 31 1579) and the diagnostic are briefly described. A series of plasma discharges with reproducible confinement transitions was created by ramping up the plasma current....

Island divertor experiments on the Wendelstein 7-AS stellarator

A promising new operational regime on the Wendelstein stellarator W7-AS has been discovered, fulfilling the conditions of optimal core behavior in combination with edge parameters suitable for successful divertor scenarios. This regime, the high density H-mode (HDH), displays no systematically evident mode activity, and is edge localized mode (ELM)-free. It is extant above a power-dependent thr...

The Set of Diagnostics for the First Operation Campaign of the Wendelstein 7-X Stellarator

Wendelstein 7-X (W7-X) is a large optimized stellarator (B=2.5T, V=30m) aiming at demonstrating the reactor relevance of the optimized stellarators. In summer this year (2015) W7-X will begin its first operation phase (OP1.1) with five inertially cooled inboard limiters made of graphite. Assuming the heat loads can be spread out evenly between the limiters, 1 second discharges at 2 MW of heatin...