Effect of 3-D fields on the divertor detachment in NSTX

Divertor plasma detachment was induced by divertor gas puffing in NSTX and is accompanied by a drop of pedestal electron temperature ($T_{e})$ and density ($n_{e})$, therefore pressure ($p_{e})$, and this drop becomes stronger, particularly in $T_{e}$, with increasing gas puffing rate. The applied 3-D fields were observed to reattach the detached plasma for lower gas puffing rates, but the divertor plasma remained detached with higher puffing rates even with the 3-D field application. The pedestal $T_{e}$ profile for the detached plasma at lower puff rates shows a clear increase during the 3-D field application while the pedestal density increase is not obvious. The 3-D field does not affect the pedestal profiles of the detached plasma at higher puff rates. The Ultra Soft X-ray (USXR) data indicates that the emission intensity first changes in the edge region, both by the detachment and 3-D field application, and then propagates into the pedestal region. The change of the transport processes both in the edge and core region across the detachment and the 3-D field application will be also investigated with diagnostic measurements available. This work was supported by the US Department of Energy, contract {\#} DE-AC05-000R22725, DE-AC02-09CH11466, DE-AC52-07NA27344, and DE-AC02-09CH11466.