Impurity transport in ion- and electron-root confinement scenarios at Wendelstein 7-X

Wendelstein 7-X and fusion

Modeling of ion-cyclotron resonant heating in Wendelstein 7-X equilibrium

W7X stellarator 3D equilibrium has been computed with the equilibrium code ANIMEC (Anisotropic Neumann Inverse Moments Equilibrium Code). This equilibrium was used to model ICRH minority heating in 4 He(H) plasma with the 3D full-wave code LEMan (Low frequency ElectroMagnetic wave propagation). The coupled power spatial distribution is shown for different resonance positions within the range of...

On Impurity Handling in High Performance Stellarator/Heliotron Plasmas

The Large Helical Device (LHD) and Wendelstein 7-X (W7-X, under construction) are experiments specially designed to demonstrate long pulse (quasi steady-state) operation, which is an intrinsic property of Stellarators and Heliotrons. Significant progress was made in establishment of high performance plasmas. A crucial point is the increasing impurity confinement towards high density as observed...

A hybrid fluid–kinetic approach for 3D plasma edge transport in He-plasma at Wendelstein 7-X

Introduction The complex three-dimensional structure of the optimised stellarator Wendelstein 7-X can only partially be accessed by means of experimental measurements, as a consequence of the only quite limited number of measurements at distinct locations with different plasma crosssections and properties. This highlights the importance of precise modelling (i.e. numerical bookkeeping) as an ex...

Spectroscopic imaging of limiter heat and particle fluxes and the resulting impurity sources during Wendelstein 7-X startup plasmas.

A combined IR and visible camera system [G. A. Wurden et al., "A high resolution IR/visible imaging system for the W7-X limiter," Rev. Sci. Instrum. (these proceedings)] and a filterscope system [R. J. Colchin et al., Rev. Sci. Instrum. 74, 2068 (2003)] were implemented together to obtain spectroscopic data of limiter and first wall recycling and impurity sources during Wendelstein 7-X startup ...