Implementation of synthetic fast-ion loss detector and imaging heavy ion beam probe diagnostics in the 3D hybrid kinetic-MHD code MEGA

TL;DR

This paper presents the implementation of synthetic fast-ion loss detector and imaging heavy ion beam probe diagnostics in the 3D hybrid kinetic-MHD code MEGA, enabling simulation of diagnostic signals and their correlation with plasma instabilities.

Contribution

The paper introduces new synthetic diagnostic tools within MEGA for fast-ion loss and heavy ion beam probing, facilitating detailed analysis of plasma behaviors and diagnostics in a 3D hybrid simulation.

Findings

Strong correlation between fast-ion losses and Alfvén Eigenmode amplitude.

Synthetic signals show measurable displacements consistent with experimental resolution.

Energy exchange diagrams reveal phase-space structures linked to plasma instabilities.

Abstract

A synthetic Fast-Ion Loss Detector (FILD) and an imaging Heavy Ion Beam Probe (i-HIBP) have been implemented in the 3D hybrid kinetic-magnetohydrodynamic code MEGA. First synthetic measurements from these two diagnostics have been obtained for neutral beam injection (NBI) driven Alfv\'en Eigenmode (AE) simulated with MEGA. The synthetic fast-ion losses show a strong correlation with the AE amplitude. This correlation is observed in the phase-space, represented in coordinates toroidal canonical momentum and energy. Fast-ion losses and the energy exchange diagrams of the confined population are connected with lines of constant E' , a linear combination of E and P{\phi} . First i-HIBP synthetic signals also have been computed for the simulated AE, showing displacements in the strikeline of the order of around 1 mm, above the expected resolution in the i-HIBP scintillator of approximately 100 {\mu}m.