Plasma Edge Physics with B2‐Eirene

Abstract

The B2‐Eirene code package was developed to give better insight into the physics in the scrape‐off layer (SOL), which is defined as the region of open field‐lines intersecting walls. The SOL is characterised by the competition of parallel and perpendicular transport defining by this a 2D system. The description of the plasma‐wall interaction due to the existence of walls and atomic processes are necessary ingredients for an understanding of the scrape‐off layer. This paper concentrates on understanding the basic physics by combining the results of the code with experiments and analytical models or estimates. This work will mainly focus on divertor tokamaks, but most of the arguments and principles can be easily adapted also to other concepts like island divertors in stellarators or limiter devices. The paper presents the basic equations for the plasma transport and the basic models for the neutral transport. This defines the basic ingredients for the SOLPS (Scrape‐Off Layer Plasma Simulator) code package. A first level of understanding is approached for pure hydrogenic plasmas based both on simple models and simulations with B2‐Eirene neglecting drifts and currents. The influence of neutral transport on the different operation regimes is here the main topic. This will finish with time‐dependent phenomena for the pure plasma, so‐called Edge Localised Modes (ELMs). Then, the influence of impurities on the SOL plasma is discussed. For the understanding of impurity physics in the SOL one needs a rather complex combination of different aspects. The impurity production process has to be understood, then the effects of impurities in terms of radiation losses have to be included and finally impurity transport is necessary. This will be introduced with rising complexity starting with simple estimates, analysing then the detailed parallel force balance and the flow pattern of impurities. Using this, impurity compression and radiation instabilities will be studied. This part ends, combining all the elements introduced before, with specific, detailed results from different machines. Then, the effect of drifts and currents is introduced and their consequences presented. Finally, some work on deriving scaling laws for the anomalous turbulent transport based on automatic edge transport code fitting procedures will be described. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Effect of E×B driven transport on the deposition of carbon in the outer divertor of ASDEX Upgrade

“…The SOLPS5.0 code package [4], with the plasma fluid code B2.5 coupled to the Monte Carlo neutrals code Eirene-99 and impurities included in the solution, was used to calculate 2D models of the divertor plasma conditions. The solutions were validated against multiple measurements at the outer target and at the outer midplane, in the two experiments described in this paper.…”

Benchmarking Tokamak edge modelling codes

“…The codes currently being compared are SOLPS ("B2.5-Eirene") [1][2][3][4][5], EDGE2D-NIMBUS [6][7][8][9] and EDGE2D-EIRENE, all with Monte-Carlo neutrals; and SOLPS ("B2.5") [10][11][12][13][14][15] and UEDGE [16], with fluid neutrals. In order to remove one possible source of differences in the codes, all of the codes are using the same grid (the standard grid generated by the JET GRID2D [6] or, for some test cases, an orthogonal grid generated by UEDGE).…”

Radiation distributions in TCV

“…Such simulations have recently been performed using the SOLPS5 (B2.5-Eirene) code package [11] for He and D plasmas in precisely the discharge configuration used here [13,12].…”