Two-point Analysis of SOLPS Modeling for a Slot Divertor

Two-Point Modeling, 2PM, is used to verify and quantify SOLPS code analysis of a narrow slot divertor configuration for a Fusion Nuclear Test Facility based on the Advanced Divertor concept, FNSF-AT [1]. The conventional 2PM includes free parameters, the power and momentum loss factors, f$_{pwr-loss}$, f$_{mom-loss}$. Kotov and Reiter showed that the 2PM is exact in the framework of the equations solved by the B2 code when f$_{pwr-loss}$ and f$_{mom-loss}$ are computed from the B2 code output [2]. An approximation of this procedure is applied here to the SOLPS analysis for FNSF-AT. As the ``upstream'' density at the outside midplane separatrix, n$_u$, is increased from 4.8e19 to 8.4e19 m$^{-3}$, the value of T$_{e-OSP}$ at the outer strike point drops from 70 to 2 eV while n$_{e\_OSP}$ increases from 2E20 to 2E21 m$^{-3}$. Over this range of conditions the 2PM values of T$_{e-OSP}$ were found to be within a factor of 2 of the SOLPS values. The relative roles of power and momentum loss are discussed.\par \vskip6pt \noindent [1] Garofalo et al, Nucl. Fusion 54 (2014) 073015.\par \noindent [2] Plasma Phys. Control. Fusion 51 (2009) 115002.