Numerical study of potential heat flux mitigation effects in the TCV snowflake divertor

We report on EMC3-Eirene simulations of the plasma and neutral particle transport the TCV boundary layer of a series of snowflake (SF) equilibria characterized by the normalized poloidal flux coordinate of the secondary X-point x2. We refer to a snowflake plus (SF+) for , a snowflake minus (SF−) for and a single-null (SN) for . Four effects are identified that have the potential to mitigate the heat flux density at the outer strike point in a LFS SF−where x2 is located on the low field side of the primary X-point x1: (1) a scrape-off layer heat flux splitting, (2) an impurity radiation cloud forming at x2 (3) the increased connection length to the outer target and (4) increased transport between x1 and x2. The LFS SF− is thus expected to tolerate a larger power flux over the separatrix than a comparable SN configuration.