TY - JOUR
T1 - Lithium surface-response modelling for the NSTX liquid lithium divertor
AU - Allain, J. P.
AU - Brooks, J. N.
PY - 2011/2
Y1 - 2011/2
N2 - We analyse lithium sputtering, evaporation and transport for the National Spherical Torus Experiment (NSTX) liquid lithium divertor (LLD) for planned high heating power plasma conditions. A temperature-dependent, datacalibrated, surface-response model is used to specify sputter yield, velocity distributions, sputtered Li ion fraction and related phenomena, for the static liquid lithium surface with D, Li and trace C impingement. Using the surfaceresponse model, and supplied UEDGE code edge plasma parameters and LLD surface temperature profile for a typical 2MW heating, low D-recycle shot, the REDEP/WBC code package computes Li erosion/redeposition. The results are encouraging showing negligible Li evaporation, moderate sputter erosion, and acceptable Li transport to the edge (̃7% Li/D density) and core plasma (̃1% Li/D contamination potential) and LLD adjacent surfaces. A 2% carbon plasma content does not significantly affect the LLD surface response. For fixed plasma conditions, but with hypothetically higher surface temperatures than the reference 281 °C peak, an increase to ̃350 °C appears acceptable, thus implying a significant operating temperature margin.
AB - We analyse lithium sputtering, evaporation and transport for the National Spherical Torus Experiment (NSTX) liquid lithium divertor (LLD) for planned high heating power plasma conditions. A temperature-dependent, datacalibrated, surface-response model is used to specify sputter yield, velocity distributions, sputtered Li ion fraction and related phenomena, for the static liquid lithium surface with D, Li and trace C impingement. Using the surfaceresponse model, and supplied UEDGE code edge plasma parameters and LLD surface temperature profile for a typical 2MW heating, low D-recycle shot, the REDEP/WBC code package computes Li erosion/redeposition. The results are encouraging showing negligible Li evaporation, moderate sputter erosion, and acceptable Li transport to the edge (̃7% Li/D density) and core plasma (̃1% Li/D contamination potential) and LLD adjacent surfaces. A 2% carbon plasma content does not significantly affect the LLD surface response. For fixed plasma conditions, but with hypothetically higher surface temperatures than the reference 281 °C peak, an increase to ̃350 °C appears acceptable, thus implying a significant operating temperature margin.
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U2 - 10.1088/0029-5515/51/2/023002
DO - 10.1088/0029-5515/51/2/023002
M3 - Article
AN - SCOPUS:79751508492
SN - 0029-5515
VL - 51
JO - Nuclear Fusion
JF - Nuclear Fusion
IS - 2
M1 - 023002
ER -