Preliminary Comparison of the Conventional and Quasi‐Snowflake Divertor Configurations with the 2D Code EDGE2D/EIRENE in the FAST Tokamak

Abstract

The new magnetic configurations for tokamak divertors, snowflake and super-X, proposed to mitigate the problem of the power exhaust in reactors have clearly evidenced the need for an accurate and reliable modeling of the physics governing the interaction with the plates. The initial effort undertaken jointly by ENEA and IPPLM has been focused to exploit a simple and versatile modeling tool, namely the 2D TECXY code, to obtain preliminary comparison between the conventional and snowflake configurations for the proposed new device FAST that should realize an edge plasma with properties quite close to those of a reactor. The very interesting features found for the snowflake, namely a power load mitigation much larger than expected directly from the change of the magnetic topology, has further pushed us to check these results with the more sophisticated computational tool EDGE2D coupled with the neutral code module EIRENE. After a preparatory work that has been carried out in order to adapt this code combination to deal with non-conventional, single null equilibria and in particular with second order nulls in the poloidal field generated in the snowflake configuration, in this paper we describe the first activity to compare these codes and discuss the first results obtained for FAST. The outcome of these EDGE2D runs is in qualitative agreement with those of TECXY, confirming the potential benefit obtainable from a snowflake configuration.

A comparison of source term estimators in coupled finite-volume/Monte-Carlo methods with applications to plasma edge simulations in nuclear fusion

“…In many applications, the relevant processes are accurately described by a partial differential equation (PDE) of reaction-advection-diffusion type coupled to a Boltzmann-type kinetic equation that models a distribution of particles in position-velocity space. Examples of such applications include bacterial chemotaxis [18], rarified gas dynamics [24], and plasma physics [17,22,25]. The simulation of such coupled models is computationally challenging due to the different dimensionality of both parts of the model.…”