Dependence of divertor heat flux widths on heating power, flux expansion, and plasma current in the NSTX

Gray, T. K.; Maingi, R.; Soukhanovskii, V. A.; Surany, J. E.; Ahn, J. -W.; McLean, A. G.

doi:10.1016/j.jnucmat.2011.01.029

Dependence of divertor heat flux widths on heating power, flux expansion, and plasma current in the NSTX

Journal Article · Fri Jan 28 00:00:00 EST 2011 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2011.01.029· OSTI ID:1898294

Gray, T. K. ^[1]; Maingi, R. ^[2]; Soukhanovskii, V. A. ^[3]; Surany, J. E. ^[4]; Ahn, J. -W. ^[2]; McLean, A. G. ^[2]

Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Princeton University, NJ (United States)

Here, we report the dependence of the lower divertor surface heat flux profiles, measured from infrared thermography and mapped magnetically to the mid-plane on loss power into the scrape-off layer (P_LOSS), plasma current (I_p), and magnetic flux expansion (f_exp), as well as initial results with lithium wall conditioning in NSTX. Here we extend previous studies to higher triangularity ~0.7 and higher I_p ≤ 1.2 MA. First we note that the mid-plane heat flux width mapped to the mid-plane, $$λ^{mid}_q$$, is largely independent of P_LOSS for P_LOSS ≥ 4 MW. $$λ^{mid}_q$$ is also found to be relatively independent of f_exp; peak heat flux is strongly reduced as f_exp is increased, as expected. Finally, $$λ^{mid}_q$$ is shown to strongly contract with increasing I_p such that $$λ^{mid}_q$$ ∝ I$$^{-1.6}_p$$ with a peak divertor heat flux of q_{div, peak} ~ 15 MW/m² when I_p = 1.2 MA and P_LOSS ~ 6 MW. These relationships are then used to predict the divertor heat flux for the planned NSTX-Upgrade, with heating power between 10 and 15 MW, B_t = 1.0 T and I_p = 2.0 MA for 5 s.

View Accepted Manuscript (DOE)

Research Organization:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: AC02-09CH11466; AC05-00OR22725; AC05-06OR23100; AC52-07NA27344

OSTI ID:: 1898294

Alternate ID(s):: OSTI ID: 21579081

Report Number(s):: LLNL-JRNL-434147; 402075

Journal Information:: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: 1 Vol. 415; ISSN 0022-3115

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

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