En route to realistic modeling of the kinetic-MHD interaction between macroscopic modes and fast particles induced by neutral beam injection in tokamaks

TL;DR

This paper introduces a new realistic model for neutral beam injection in tokamaks within a hybrid kinetic-MHD code, enabling better simulation of fast particle interactions with macroscopic modes, validated against experimental data.

Contribution

The paper develops and validates a comprehensive NBI fast ion source model integrated into the XTOR-K code for realistic tokamak simulations.

Findings

Resonance between passing particles and the n=1 mode partially stabilizes the kink mode.

NBI induces a toroidal torque with minimal impact on kink mode dynamics in ITER-like geometry.

Model validation performed using ASDEX Upgrade experimental data.

Abstract

A new model of fast ion source induced by Neutral Beam Injection (NBI) in tokamaks has been implemented in the hybrid kinetic-magnetohydrodynamic code XTOR-K. This source, combined with the collisions also recently implemented, allows for the modeling of realistic slowing-down populations and their interplay with macroscopic modes. This paper describes the Neutral Beam injection and ionization model designed to reproduce experimental configurations and its validation for a typical discharge of the ASDEX Upgrade tokamak. The application to the interaction of NBI-induced fast particles with a kink mode in ASDEX Upgrade demonstrates a resonance between passing particles and the n=1 mode. This resonance partially stabilizes the kink mode and induces a radial transport of fast particles. Preliminary results in ITER-like circular geometry show that NBI induces a toroidal torque but has little impact on the kink mode dynamics.