Faraday shield dissipation in the drivers of SPIDER based on electromagnetic 3D calculations

TL;DR

This paper uses 3D electromagnetic calculations to evaluate RF power dissipation in the Faraday shield of SPIDER, a prototype ion source, revealing that about half of the RF power is absorbed by the copper shield, with potential efficiency improvements.

Contribution

It provides the first detailed 3D electromagnetic analysis of RF power dissipation in SPIDER's Faraday shield, correlating calculations with experimental calorimetry data.

Findings

FSLW absorbs around 50% of RF power under studied conditions

Agreement between calculations and calorimetry data

Potential for efficiency improvements with better confinement

Abstract

SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma) is a full-scale prototype of the ITER NBI source. It is based on the concept of inductive coupling between radio-frequency current drive and plasma. Present three-dimensional (3D) electromagnetic calculations of stationary RF fields in SPIDER permit an evaluation of the power dissipation in its main constituents. Taking experimental plasma parameters as input, we concentrate on the power dissipation in the copper-made Faraday shield lateral wall (FSLW) of the source for discharges with and without a static magnetic filter field. In agreement with our previous results and a first comparison with calorimetry data from the FSLW cooling circuit, the FSLW cylinder alone absorbs around 50\% of the available power for the studied plasma parameters. A hypothesized improvement of transport confinement may increase significantly the efficiency.