Globus-M Experiments With Pre-Damaged Tungsten Divertor

Abstract

Divertor targets composed of pre-damaged tungsten (W) tiles were prepared and installed at an outer strike point region of a Globus-M lower divertor. An electron beam was used to irradiate the W tiles close to influence of 1000-2000 disruption events in ITER. Providing adequacy of the e-beam thermal load to the real ITER conditions, the pre-damage treatment was simulated by ANSYS Multiphysics software. The W e-beam treatment results in melting of surface layers, shrinkage and fatigue intergranular cracking of the metal, void formation, grain ordering, and decreasing of microhardness. The first test of the pre-damaged W targets in the Globus-M divertor showed pronounced non-uniform heating caused by plasma disruption events. Temperature field formation may be explained by non-uniform thermal conductivity of the damaged layer or interface between the layer and undamaged bulk structure. One of the most important effects of the pre-damaged W installation is no significant changes in Globus-M discharge behavior.