An asymptotic-preserving 2D-2P relativistic drift-kinetic-equation solver for runaway electron simulations in axisymmetric tokamaks. (English) Zbl 07524770
Summary: We propose an asymptotic-preserving (AP), uniformly convergent numerical scheme for the relativistic collisional Drift-Kinetic Equation (rDKE) to simulate runaway electrons in axisymmetric toroidal magnetic field geometries typical of tokamak devices. The approach is derived from an exact Green’s function solution with numerical approximations of quantifiable impact, and results in a simple, two-step operator-split algorithm, consisting of a collisional Eulerian step, and a Lagrangian orbit-integration step with analytically prescribed kernels. The AP character of the approach is demonstrated by analysis of the dominant numerical errors, as well as by numerical experiments. We demonstrate the ability of the algorithm to provide accurate answers regardless of plasma collisionality on a circular axisymmetric tokamak geometry.
MSC:
| 82Cxx | Time-dependent statistical mechanics (dynamic and nonequilibrium) |
| 65Mxx | Numerical methods for partial differential equations, initial value and time-dependent initial-boundary value problems |
| 82Dxx | Applications of statistical mechanics to specific types of physical systems |
Keywords:
relativistic drift-kinetic equation; runaway electrons; relativistic collisions; Vlasov-Fokker-Planck; asymptotic preservation; semi-Lagrangian algorithmsReferences:
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