An iterative algorithm of coupling the Kinetic Code for Plasma Periphery (KIPP) with SOLPS

Abstract

Power exhaust is one of the critical issues for future fusion devices, e.g. ITER.The calculation of power deposition is critical for the divertor design. SOLPS is the main tool for predictions of the Scrape-off Layer (SOL) and divertor conditions in the future fusion device ITER, where parallel kinetic effects in the SOL will play an important role. SOLPS uses a collisional fluid model which does not take kinetic effects into account. The present work has enabled SOLPS in its 1D version to incorporate electron kinetic effects by coupling it with the Kinetic Code for Plasma Periphery (KIPP). An iterative algorithm, which is made as an automatic process, is investigated in this work.

Implementation of an inelastic collision operator into KIPP‐SOLPS coupling and its effects on electron parallel transport in the scrape‐off layer plasmas

“…In order to run SOLPS with kinetic electron effects, an iterative coupling algorithm was introduced in ref. . Compared to the fluid model solved in SOLPS, this algorithm treats electron parallel transport fully kinetically by calculating four electron‐related kinetic factors: electron heat conduction coefficient c e , thermal force coefficient k ∥ , sheath potential drop coefficient δ ϕ , and electron sheath heat transmission coefficient γ e , with KIPP and transferring them back to SOLPS.…”

“…A previous study fully investigated the KIPP‐SOLPS coupling algorithm, and kinetic effects of parallel electron transport were presented in ref. .…”

“…The coupling simulation geometry is taken from ref. , which is a 1D rectangular box with the “stagnation point” and the “target” as left and right boundaries, respectively, corresponding to a flux tube from the outer mid‐plane to the target with poloidal length L pol = 2.5 m and parallel length L par ≈ 25 m. There are 127 cells non‐uniformly distributed, with coarser cells upstream and finer cells near the target.…”

“…The Kinetic Code for Plasma Periphery (KIPP), which is a continuum kinetic code solving the Vlasov–Fokker–Planck equation with high accuracy of collision terms for electron parallel transport, was coupled with SOLPS based on an iterative coupling algorithm, briefly described in Section 2. The KIPP‐SOLPS coupling algorithm enables one to treat electron parallel transport fully kinetically while still retaining all the physics that SOLPS has, which would be time consuming to capture using a kinetic code, and is accurately captured by the fluid code.…”

“…The KIPP‐SOLPS coupling algorithm enables one to treat electron parallel transport fully kinetically while still retaining all the physics that SOLPS has, which would be time consuming to capture using a kinetic code, and is accurately captured by the fluid code. In previous studies, the KIPP‐SOLPS coupling algorithm was extensively investigated. The atomic physics was treated in SOLPS code, and the corresponding electron cooling due to ionization, line radiation, and recombination‐bremsstrahlung radiation was included in KIPP by a uniform power removal scheme, as described in Section 2, which was, however, not realistic, especially for plasmas downstream near the target.…”