Drift-based scrape-off particle width in X-point geometry

Reiser, D.; Eich, T.

doi:10.1088/1741-4326/aa5ab7

Journal Article

FZJ-2017-01944

Drift-based scrape-off particle width in X-point geometry

Reiser, D. (Corresponding author)FZJ* ; Eich, T.

2017
IAEA Vienna

Nuclear fusion 57(4), 046011 - (2017) [10.1088/1741-4326/aa5ab7]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/23418 doi:10.1088/1741-4326/aa5ab7

Abstract: The Goldston heuristic estimate of the scrape-off layer width (Goldston 2012 Nucl. Fusion 52 013009) is reconsidered using a fluid description for the plasma dynamics. The basic ingredient is the inclusion of a compressible diamagnetic drift for the particle cross field transport. Instead of testing the heuristic model in a sophisticated numerical simulation including several physical mechanisms working together, the purpose of this work is to point out basic consequences for a drift-dominated cross field transport using a reduced fluid model. To evaluate the model equations and prepare them for subsequent numerical solution a specific analytical model for 2D magnetic field configurations with X-points is employed. In a first step parameter scans in high-resolution grids for isothermal plasmas are done to assess the basic formulas of the heuristic model with respect to the functional dependence of the scrape-off width on the poloidal magnetic field and plasma temperature. Particular features in the 2D-fluid calculations—especially the appearance of supersonic parallel flows and shock wave like bifurcational jumps—are discussed and can be understood partly in the framework of a reduced 1D model. The resulting semi-analytical findings might give hints for experimental proof and implementation in more elaborated fluid simulations.

Classification: