Berlin 2014 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 11: Magnetic Confinement II
P 11.3: Fachvortrag
Dienstag, 18. März 2014, 15:00–15:25, SPA HS202
The snowflake divertor, physics of a new concept for power exhaust of fusion plasmas — •Tilmann Lunt1, Gustavo Canal2, Yühe Feng1, and Holger Reimerdes2 — 1Max-Planck-Institut für Plasmaphysik, Garching/Greifswald, Germany — 2Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Fusion reactors based on the tokamak design will have to deal with very high heat loads on the divertor plates. One of the approaches to solve this heat load problem is the so called ‘snowflake divertor’, a magnetic configuration with two nearby x-points and two additional divertor legs. In this contribution we report on ‘EMC3-Eirene’ simulations of the plasma- and neutral particle transport in the scrape-off layer of the swiss tokamak TCV of a series of snowflake equilibria with different values of σ, the distance between the x-points normalized to the minor radius of the plasma. The constant anomalous transport coefficients were chosen such that the power- and particle deposition profiles at the primary inner strike point match the Langmuir probe measurements for the σ=0.1 case. At one of the secondary strike points, however, a significantly larger power flux than that predicted by the simulation was measured by the probes, indicating the presence of an enhanced transport across the primary separatrix. We will discuss the possible reason for this enhanced transport as well as its scaling with machine size. Another prediction from the simulation is that the density as well as the radiation maximum are moving from the recycling region in front of the plates upwards to the x-point.