Numerical analysis of JET discharges with the European Transport Simulator

Abstract

The "European Transport Simulator" (ETS) [1,2] is the new modular package for 1-D discharge evolution developed within the EFDA Integrated Tokamak Modelling (ITM) Task Force. It consists of precompiled physics modules combined into a workflow through standardized input/output data-structures. Ultimately, the ETS will allow for an entire discharge simulation from the start up until the current termination phase, including controllers and sub-systems. The paper presents the current status of the ETS towards this ultimate goal. It discusses the design of the workflow, the validation and verification of its components on the example of impurity solver and demonstrates a proof-of-principles coupling of a local gyrofluid model for turbulent transport to the ETS. It also presents first results on the application of the ETS to JET tokamak discharges with ITER like wall. It studies the correlations of the radiation from impurity to the choice of the sources and transport coefficients. ETS transport solver and workflow designThe ETS adopts a modular approach, where standalone precompiled physics modules ('actors' in the context of the workflow) are coupled into the workflow through standardised interfaces linked with the ITM data-structure. In view of allowing collective development of

Modelling neutral beams in fusion devices: Beamlet-based model for fast particle simulations

“…Because the sources can affect the plasma temperature and density and, consequently, the ionization and slowing down of the neutral beam, the NBI source has to be operated in a continuous fashion, with thermalized particles leaving and freshly ionized ones continuously entering the system. This is how NUBEAM operates within TRANSP, and also how ASCOT operates when it is used as the fast ion module within the JINTRAC simulation environment [30,31] and, in the future, within the European Transport Simulator (ETS) [32,33]. In this work, however, we want to find the steady-state profiles of various quantities of interest.…”

“…at JET. Future work also includes using BBNBI and ASCOT to cater for the neutral beam ionization and slowing down modelling needs of European Transport Simulator (ETS) [33,32] within the EFDA Integrated Tokamak Modelling framework (ITM) [11]. Benchmarking BBNBI and ASCOT against other similar tools adapted to the ITM standards will be an integral part of this effort.…”

On the challenge of plasma heating with the JET metallic wall

“…Particularly as ICRF led to strongly peaked electron temperature profiles and strong sawtooth activity. A complete transport analysis of the pulses here presented is outside the scope of this paper nevertheless the following results were obtained so far for pulse 81856 (assuming that the ion temperature T i is equal to T e , as no T i measurements were available): -The European transport simulator (ETS) was used [45] assuming similar impurities transport coefficient for the NBI and ICRF phase (computed from a Bohm-GyroBohm modelanalytical description for anomalous transport). The main conclusion being that best agreement with the radiated power and effective charge experimental profiles could be obtained by assuming during the ICRF an increased boundary impurity source (and zero convective velocity) although the effect of a radially shaped convective velocity that was not investigated, could not be excluded.…”

The European Integrated Tokamak Modelling (ITM) effort: achievements and first physics results

“…A demonstration of ITM progress towards turbulencetransport workflows with the ETS core transport solver is given in [28]. A parallel effort within a different scientific workflow framework is presented in [29].…”

“…The sequence of operations of the workflow core, shown in Figure 9, is detailed in the following. Here, BPROFS is the transport equilibration model, used in place of the ETS module implemented in [28], [29]. The UALINIT actor is executed only once, at the beginning, to read the input data from the database; it provides the initial coreprof_CPO and equilibrium_CPO at the initial time (for time steps after the first one, the "coreprof" and "equilibrium" boxes shown at the top replace the UALINIT actor, representing the previous step's output ).…”