Runaway Electron Control in FTU

TL;DR

This paper presents experimental results on controlling runaway electrons in FTU, using new real-time algorithms to reduce RE-plasma interactions during disruptions, with analysis of their effectiveness across multiple discharges.

Contribution

Introduction of novel real-time runaway electron control algorithms tested in disruption scenarios at FTU, improving RE beam management and plasma safety.

Findings

Effective RE control algorithms reduce RE-plasma interactions.

Disruption-generated RE plateaus can be managed with real-time control.

Control strategies show consistent performance across 52 discharges.

Abstract

Experimental results on the position and current control of disruption generated runaway electrons (RE) in FTU are presented. A scanning interferometer diagnostic has been used to analyze the time evolution of the RE beam radial position and its instabilities. Correspondence of the interferometer time traces, radial profile reconstructed via magnetic measurements and fission chamber signals are discussed. New RE control algorithms, which define in real-time updated plasma current and position references, have been tested in two experimental scenarios featuring disruption generated RE plateaus. Comparative studies among 52 discharges with disruption generated RE beam plateaus are presented in order to assess the effectiveness of the proposed control strategies as the RE beam interaction with the plasma facing components is reduced while the current is ramped-down.