Simulation of plasma–surface interactions in a fusion reactor by means of QSPA plasma streams: recent results and prospects

Abstract

This paper is devoted to plasma-surface interaction issues at high heat-loads which are typical for fusion reactors. For the International Thermonuclear Experimental Reactor (ITER), which is now under construction, the knowledge of erosion processes and the behaviour of various constructional materials under extreme conditions is a very critical issue, which will determine a successful realization of the project. The most important plasma-surface interaction (PSI) effects in 3D geometry have been studied using a QSPA Kh-50 powerful quasi-stationary plasma accelerator. Mechanisms of the droplet and dust generation have been investigated in detail. It was found that the droplets emission from castellated surfaces has a threshold character and a cyclic nature. It begins only after a certain number of the irradiating plasma pulses when molten and shifted material is accumulated at the edges of the castellated structure. This new erosion mechanism, connected with the edge effects, results in an increase in the size of the emitted droplets (as compared with those emitted from a flat surface). This mechanism can even induce the ejection of sub-mm particles. A concept of a new-generation QSPA facility, the current status of this device maintenance, and prospects for further experiments are also presented.

Parameters of Hydrogen Plasma Streams in Qspa-M and Their Dependence on External Magnetic Field

“…The QSPA-M plasma accelerator, as compare with other available QSPA devices, is equipped with magnetic coils creating the external longitudinal B-field up to 1T. Ability of QSPA-M to operate with additional external strong external magnetic field allows simulation of the divertor plasma flows along the Bfield linesduring the transient events in ITER and DEMO reactors and predictive testing of candidate materials under powerful plasma exposures [7][8][9].…”

Modification and Alloying Effects in Eurofer Steel Under Powerful Pulsed Plasma Impacts

“…Earlier such coatings were applied for estimations of their performance as plasma facing surfaces (in a comparison with monolithic tungsten targets). They enabled also an analysis of the adhesion properties of the PVD coatings, and an investigation of the plasma facing components prospective for the reactor first wall construction [8].…”

“…Surface modifications by powerful pulsed plasma streams were carried out with the use of a QSPA Kh-50 quasi-stationary plasma accelerator [8]. The main parameters of the QSPA hydrogen plasma streams were as follows: ion impact energy was about 0.4…0.6 keV, the maximum plasma pressure reached up to 0.32 MPa, and the plasma stream diameter was about 18 cm.…”

Changes of the Radiation Characteristics of Surface of Tungsten as a Result of Influence of Helium Ion Beams

“…At consideration of perspective materials for creation of the first wall of thermonuclear reactor tungsten is a promising candidate. It has several specific properties that allow its use in thermonuclear reactors [3][4][5][6][7][8][9].…”