Bremen 2017 – scientific programme

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P: Fachverband Plasmaphysik

P 2: Helmholtz Graduate School I

P 2.5: Talk

Monday, March 13, 2017, 10:10–10:35, HS 1010

Fictitious time-evolution for steady-state strongly non-linear transport equations — •Herbert Oberlin, Marco Restelli, and Omar Maj — Max Planck Institut - IPP , Garching bei München, Deutschland

The solution of nonlinear partial differential equations may often pose difficult challenges in the development of efficient codes for physics simulations. Standard methods usually rely on iterative schemes that, in time-dependent problems are nested into time-stepping iterations. In strongly non-linear cases, convergence of the iterative nonlinear solver imposes prohibitively small values for the time-step. When only the steady state is of interest, this amounts to wasting resources in the uninteresting transient. In this work, we propose new relaxation methods for the computation of steady-state solutions for strongly non-linear systems, based on the dissipation of specific metrics of the system which guarantee better steady-state convergence properties. The main envisaged application is the speeding up of the computational fluid dynamics kernel of the SOLPS (Scrape-Off Layer Plasma Simulation) suite of codes which simulate the outer region of the plasma column in tokamak devices.