Operational status of the Magnum-PSI linear plasma device

Abstract

h i g h l i g h t s• High heat flux, high density plasmas in a highly accessible linear plasma device.• Plasma exposure of targets of different sizes under selectable plasma beam angles.• Dedicated plasma and surface diagnostics.• Differential vacuum pumping system. a r t i c l e i n f o b s t r a c tThe construction phase of the linear plasma generator Magnum-PSI at the FOM institute DIFFER has been completed and the facility has been officially opened in March 2012. The scientific program to gain more insight in the plasma-wall interactions relevant for ITER and future fusion reactors has started.In Magnum-PSI, targets of a wide range of materials and shapes can be exposed to high particle, high heat flux plasmas (>10 24 ions m −2 s −1 ; >10 MW/m 2 ). For magnetization of the plasma, oil-cooled electromagnets are temporarily installed to enable pulsed operation until the device is upgraded with a superconducting magnet. The magnets generate a field of up to 1.9 T close to the plasma source for a duration of 6 s. Longer exposure times are available for lower field settings.Plasma characterizations were done with a variety of gases (H, D, He, Ne and Ar) to determine the machine performance and prepare for subsequent scientific experiments. Thomson scattering and optical emission spectroscopy were used to determine the plasma parameters while infrared thermography and target calorimetry were used to determine the power loads to the surface. This paper reports on the status of Magnum-PSI and its diagnostic systems. In addition, an overview of the plasma parameters that can be achieved in the present state will be given.

Thermal annealing and exposure to divertor-like deuterium plasma of tailored tungsten oxide coatings

“…A K-Thermocouple is used to monitor the stage temperature. WO x coatings, deposited on W substrates and not annealed, were exposed to high-flux deuterium plasmas in the linear plasma generator Magnum-PSI at FOM-DIFFER [22,23] at low surface temperature (maximum temperature in center of plasma beam of T max = 580 K). The electron density and temperature of the plasma were measured with Thomson scattering [24].…”

The effect of high-flux H plasma exposure with simultaneous transient heat loads on tungsten surface damage and power handling

“…The increase in ∆T is illustrated in figure 9 where 50 laser pulses at F HF = 25.2 MJ m −2 s −1/2 are applied in combination with steady-state plasma exposure. The slight decrease in base temperature through the discharge is due to a diminishing magnetic field strength leading to a decrease in power input to the plasma [13,25]. This should have no effect on the transient temperature rise induced by the laser.…”

Deuterium retention in tungsten exposed to mixed D + N plasma at divertor relevant fluxes in Magnum-PSI

“…This study aims to bridge such a gap by performing experiments using the Magnum-PSI device [11] relevant to inter-ELM radiative divertor conditions in ITER. The results clearly demonstrate that surface impurities (N or Mo) increases D retention in W due to enhanced trapping at the near surface as well as increased retention in the bulk.…”