Test particles dynamics in the JOREK 3D non-linear MHD code and application to electron transport in a disruption simulation

Abstract

In order to contribute to the understanding of runaway electron generation mechanisms during tokamak disruptions, a test particle tracker is introduced in the JOREK 3D non-linear MHD code, able to compute both full and guiding center relativistic orbits. Tests of the module show good conservation of the invariants of motion and consistency between full orbit and guiding center solutions. A first application is presented where test electron confinement properties in a JET massive gas injection-triggered disruption simulation are investigated. It is found that electron populations initialised before the thermal quench (TQ) are typically not fully deconfined in spite of the global stochasticity of the magnetic field during the TQ. The fraction of "survivors" decreases from few tens down to a few tenths of percent as the electron energy varies from 1keV to 10MeV. The underlying mechanism for electron "survival" is the prompt reformation of closed magnetic surfaces at the plasma core and, to a smaller extent, the subsequent reappearance of a magnetic surface at the edge. It is also found that electrons are less deconfined at 10MeV than at 1MeV which appears consistent with a phase averaging effect due to orbit shifts at high energy.

References in corpus (9)

• Structure and structure-preserving algorithms for plasma physics
• Coupling JOREK and STARWALL for Non-linear Resistive-wall Simulations
• Hamiltonian Theory of Adiabatic Motion of Relativistic Charged Particles
• Synchrotron radiation from a runaway electron distribution in tokamaks
• High order volume-preserving algorithms for relativistic charged particles in general electromagnetic fields
• Compact formulas for guiding-center orbits in axisymmetric tokamak geometry
• Linear MHD stability studies with the STARWALL code
• An advection-diffusion model for cross-field runaway electron transport in perturbed magnetic fields
• Multi-scale Full-orbit Analysis on Phase-space Behavior of Runaway Electrons in Tokamak Fields with Synchrotron Radiation

Cited by in corpus (10)

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• Simulating the nonlinear interaction of relativistic electrons and tokamak plasma instabilities: Implementation and validation of a fluid model
• First predictive simulations for deuterium shattered pellet injection in ASDEX Upgrade
• Confinement of passing and trapped runaway electrons in the simulation of an ITER current quench
• A fluid-kinetic framework for self-consistent runaway-electron simulations
• Filamentary plasma eruptions and the heating and acceleration of electrons
• Runaway electron modelling in the self-consistent core European Transport Simulator, ETS
• First numerical analysis of runaway electron generation in tungsten-rich plasmas towards ITER