First numerical analysis of runaway electron generation in tungsten-rich plasmas towards ITER
Journal article, 2024

The disruption and runaway electron analysis model code was extended to include tungsten impurities in disruption simulations with the aim of studying the runaway electron (RE) generation. This study investigates RE current sensitivity on the following plasma parameters and modelling choices: tungsten concentration, magnetic perturbation strength, electron modelling, thermal quench time and tokamak geometry—ITER-like or ASDEX-like. Our investigation shows that a tungsten concentration below 10−3 does not cause significant RE generation on its own. However, at higher concentrations it is possible to reach a very high RE current. Out of the two tested models of electrons in plasma: fluid and isotropic (kinetic), results from the fluid model are more conservative, which is useful when it comes to safety analysis. However, these results are overly pessimistic when compared to the isotropic model, which is based on a more reliable approach. Our results also show that the hot-tail RE generation mechanism is dominant as a primary source of RE in tungsten induced disruptions, usually providing orders of magnitude higher RE seed than Dreicer generation. We discuss best practices for simulations with tungsten-rich plasma, present the dependence of the safety limits on modelling choices and highlight the biggest shortcoming of the current simulation techniques. The obtained results pave the way for a wider analysis of tungsten impact on the disruption dynamics, including the mitigation techniques for ITER in the case of strong contamination of the plasma with tungsten.

ITER

computational plasma physics

tungsten impurities

runaway electrons

Author

J. Walkowiak

Polish Academy of Sciences

National Centre for Nuclear Research

M. Hoppe

Royal Institute of Technology (KTH)

Ida Ekmark

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

A. Jardin

Polish Academy of Sciences

J. Bielecki

Polish Academy of Sciences

K. Król

Polish Academy of Sciences

Y. Savoye-Peysson

The French Alternative Energies and Atomic Energy Commission (CEA)

D. Mazon

The French Alternative Energies and Atomic Energy Commission (CEA)

D. Dworak

Polish Academy of Sciences

M. Scholz

Polish Academy of Sciences

Nuclear Fusion

0029-5515 (ISSN) 1741-4326 (eISSN)

Vol. 64 3 036024

Implementation of activities described in the Roadmap to Fusion during Horizon Europe through a joint programme of the members of the EUROfusion consortium

European Commission (EC) (101052200), 2021-01-01 -- 2025-12-31.

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/1741-4326/ad24a0

More information

Latest update

2/23/2024