IC/P4-8 A Snowflake Divertor: a Possible Way of Improving the Power Handling in Future Fusion Facilities

Handling high power loads on plasma facing components is one of the critical issues in developing an economically competitive fusion reactor or fusion test facilities based on a tokamak. In this study, we provide a detailed analysis of a relatively unexplored approach to this problem based on the use of divertors with the poloidal magnetic field structure closely approaching a second-order null. We demonstrate that this geometry opens up new possibilities for radiative divertors, has favorable effect on the plasma transport, and provides an additional control over ELM activity. In the ideal case where the null is exactly second order, the separatrix near the null acquires a characteristic hexagonal shape reminiscent of a snowflake, whence the name of this configuration. It can be created by a simple set of divertor coils situated outside the toroidal field coils.