Operational characteristics of the superconducting high flux plasma generator Magnum-PSI

Abstract

The interaction of intense plasma impacting on the wall of a fusion reactor is an area of high and increasing importance in the development of electricity production from nuclear fusion. In the Magnum-PSI linear device, an axial magnetic field confines a high density, low temperature plasma produced by a wall stabilized DC cascaded arc into an intense magnetized plasma beam directed onto a target. The experiment has shown its capability to reach conditions that enable fundamental studies of plasma-surface interactions in the regime relevant for fusion reactors such as ITER: 10 23-10 25 m-2 s-1 hydrogen plasma flux densities at 1-5 eV for tens of seconds by using conventional electromagnets. Recently the machine was upgraded with a superconducting magnet, enabling steady-state magnetic fields up to 2.5 T, expanding the operational space to high fluence capabilities for the first time. Also the diagnostic suite has been expanded by a new 4-channel resistive bolometer array and ion beam analysis techniques for surface analysis after plasma exposure of the target. A novel collective Thomson scattering system has been developed and will be implemented on Magnum-PSI. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented.

Scanning electron microscopy analyses of an ITER plasma-facing unit mockup exposed to extreme ion fluences in Magnum-PSI

“…The quasi continuous plasma exposures were performed in Magnum-PSI (with interruption for realignment of diagnostics and during the night) [2,3,6]. Details for the six exposures are given in Tab.…”

“…A small-scale mockup of the ITER divertor plasma-facing units, consisting of seven tungsten monoblocks brazed on to a CuCrZr cooling tube, was exposed to a variety of high fluence, high flux plasma loads in Magnum-PSI [2,3,6]. Six exposures were performed including H, He, D and D:He (95:5) plasmas with low electron temperature (1.5-5 eV) and high electron density (1×10 20 -2×10 21 m -3 ), resulting in a maximum surface temperature in the range 750-1600 °C (Tab.…”

“…This is in particular true for the case of actively cooled components, for which the thermal gradient will affect the diffusion into the bulk. Following the installation of superconducting magnetic field coils at Magnum-PSI, it is now possible for the first time to explore the high fluence regime within reasonable machine time of ~20 h continuous exposure [2,3].…”

Comparison between SOLPS-ITER and B2.5-Eunomia for simulating Magnum-PSI

“…Different diagnostics are applied during a typical operation of Magnum-PSI, including Thomson Scattering near the target [5]. In a typical Magnum-PSI run, a Hydrogen plasma is generated at the source chamber by a cascaded arc source [6].…”

In-situ LIBS and NRA deuterium retention study in porous W-O and compact W coatings loaded by Magnum-PSI

“…In order to comply to the safety regulations, the total retained tritium (T) in the reactor vessel should be monitored to assure that the amount of tritium in the ITER vessel does not exceed the limit of 700 g. ITER will use two hydrogen isotopes, deuterium D and tritium T to fuel the fusion reaction. The fuel retention in ITER divertor walls exposed with plasma fluxes up to 10 24 ions/m 2 s can be systematically studied in the linear plasma devices with D plasma [4,5]. The retention is strongly influenced by the properties of wall materials, i.e.…”