The effect of plasma surface interactions on plt plasma parameters

Abstract

In the four years of operation of the PLT tokamak , plasma parameters and machine operating conditions have been importantly affected by changes in the choice of limiter material and by the mode of vacuum vessel conditioning. Tungsten, stainless stuel, and graphite limiters have been used. The fractional power lost by radiation and the source distribution of the radis.tion vary strongly with limiter material, wall *UKAEA CuliVitn Laboratory, Abingdon, UK. **Exxon Co., USA. ***On leave from Max-Planck Institut fur Plasmaphysik, Garching, 7RG. When the injected gas is changed from D_ to H,, the time constant for disappearance of neutron emission can be slow (35 pulses for a reduction by a factor of three) or fast '4 pulses for a similar factor), depending on previous history of wall treatment.

Probe measurements of the density and temperature profiles in the JET plasma boundary

“…However, the figures do suggest an increasing fraction of (P^ -P R ) going to the limiters with increasing edge density, and that most power is accounted for, at edge densities n e (0) > 3 X 10 18 cm" 3 . In the other cases the power balance is unaccounted for, as is often observed in tokamaks [14]. In the absence of P d data, y I s T e is assumed with 7=10.…”

Divertor tungsten tile melting and its effect on core plasma performance

“…Tungsten has been the obvious choice for reactor plasma-facing components (PFCs) due to its high melting temperature, low tritium retention, relatively low nuclear activation, and low sputtering erosion rate ( [1] and references therein). This led early limiter tokamaks such as PLT [2] and Alcator A [3] to use tungsten and molybdenum (similar refractory metal) for PFCs. The high core radiation levels in PLT were enough that most tokamaks, other than Alcator C [4], FTU [5] and Alcator C-Mod [6] (the first diverted tokamak with high-Z PFCs), switched to carbon PFCs.…”