Topic/Type: 1.2 Fusion Plasmas (magnetic & inertial confinement), Invited

The European Transport Solver

D.P. Coster1, IMP32, TF-ITM teams2

1 Max-Planck-Institut fur Plasmaphysik, EURATOM Association, Garching, Germany
2 EFDA Task Force on Integrated Tokamak Modelling.

The European Transport Solver (ETS) is a new 1d core transport codes being developed by members of Integrated Modelling Project 3 (Transport Code and Discharge Evolution) of the EFDA Task Force on Integrated Tokamak Modelling (ITM). The approach taken by the ITM is to couple codes so that the only exchange is via well specified data structures (CPOs, Consistent Physical Ob jects), with the aim of having the workflow managed by Kepler, a Scientific Workow engine.

Thus the work of the ETS group is both to prepare the core 1d transport solver, and, in conjunction with other parts of the ITM, to prepare workflows using the ETS. The ITM has defined the CPO denitions for the physics inputs and outputs for a number of physics areas. Those relevant for the ETS include: (a) equilibrium, (b) core sources, (c) core transport, (d) core profile, (e) neoclassical transport, and (f ) core impurities.

The current version of the core ETS code expects to receive as input: (a) equilibrium CPOs representing the equilibrium at the previous time-step, and at the present iteration; (b) core source and transport CPOs representing the sources of current, particles, momentum and electron and ion energies, as well as the transport coecients of these quantities represented as difusion coeficients and convective velocities at the present iteration; (c) the plasma state as represented by the core prole at the previous time step and the previous iteration. It then returns an updated plasma state in a new core prole.
In addition to the core ETS routine, the ETS group within IMP3 has also prepared a number of workflows represented by code wrappers (these will ultimately be converted to Kepler workflows).

The first of these encompasses an analytical test case where the method of manufactured solutions is used to prepare an analytical solution to the test problem which can then be compared to the numerical solution. The test case incorporates a time varying problem with coupled poloidal flux, ion density, toroidal velocity and electron and ion temperature equations.

The second workflow takes sources and transport coecients from a previously saved case in the ITM data-base, and then solves for the poloidal flux, density, velocity and temperatures including self-consistent calculations of the equilibrium (or with a cylindrical equilibrium). For these cases, the results are compared with the results from the ASTRA 1d core transport code (or with analytical results).

One of the features of the ETS is that internally there is a separation of the physics and the numerics. All of the equations are cast in the same form characterized by a number of vectors of coeficients, and these are then passed to one of the implemented solvers.