Modeling and simulation of a beam emission spectroscopy diagnostic for the ITER prototype neutral beam injector

TL;DR

This paper presents a numerical model for simulating beam emission spectroscopy diagnostics to optimize and evaluate the performance of the ITER neutral beam injector prototypes, focusing on the MITICA experiment.

Contribution

The paper introduces a detailed numerical simulation model for the beam emission spectroscopy diagnostic specific to the ITER neutral beam injector prototypes.

Findings

Modeled Hα spectra for MITICA experiment.

Diagnostic performance insights for beam uniformity and divergence.

Guidance for optimizing the spectroscopy diagnostic design.

Abstract

A test facility for the development of the Neutral Beam Injection system for ITER is under construction at Consorzio RFX. It will host two experiments: SPIDER, a 100 keV H-/D- ion RF source, and MITICA, a prototype of the full performance ITER injector (1 MV, 17 MW beam). A set of diagnostics will monitor the operation and allow to optimize the performance of the two prototypes. In particular, Beam Emission Spectroscopy will measure the uniformity and the divergence of the fast particles beam exiting the ion source and travelling through the beam line components. This type of measurement is based on the collection of the H{\alpha}/D{\alpha} emission resulting from the interaction of the energetic particles with the background gas. A numerical model has been developed to simulate the spectrum of the collected emissions in order to design this diagnostic and to study its performance. The paper describes the model at the base of the simulations and presents the modeled $H_\alpha$ spectra in the case of MITICA experiment.