6–10 Sept 2021
Varenna, Villa Monastero
Europe/Rome timezone

Short_Oral_36: Runaway electron velocity-space observation regions of bremsstrahlung hard X-ray spectroscopy

8 Sept 2021, 17:20
10m
Villa Monastero (Varenna, Villa Monastero)

Villa Monastero

Varenna, Villa Monastero

Short oral in replacement of poster

Speaker

Enrico Panontin

Description

The reconstruction of the distribution function of runaway electrons (RE) in magnetically confined fusion plasmas can give insights on the runaway electron beam dynamics during plasma disruptions and it may help at understanding the effect of disruption mitigation techniques on the RE velocity space. When RE are assumed to be purely co-passing, i.e. to have a pitch=1, a one dimensional inversion technique can be used to infer their energy distribution function from the bremsstrahlung spectrum. However, this holds only as an approximation, as the bremsstrahlung cross section depends also on the pitch of the electrons, besides energy, and this may deviate from unity. In view of enabling a two-dimensional, energy-pitch reconstruction of the RE velocity space, in this work we present a calculation of the weight functions for the bremsstrahlung emission by the RE. The weight functions allow bridging the bremssstrahlung spectrum with the RE velocity space, as they tell the region of the velocity space that contributes to a particular spectral measurement. The results are applied to investigate the RE velocity-space sensitivity of the hard X-ray diagnostic installed at the Joint European Torus.

Primary authors

Enrico Panontin Massimo Nocente (Dipartimento di Fisica - Università di Milano-Bicocca) Andrea Dal Molin Prof. Jacob Eriksson (Department of Physics and Astronomy, Uppsala University, Sweden) Giuseppe Gorini (Universita' degli Studi di Milano-Bicocca) Enrico Perelli Cippo (Istituto per la Scienza e Tecnologia dei Plasmi - CNR) Dr Davide Rigamonti (ISTP CNR) Mirko Salewski (Technical University of Denmark) Dr Marco Tardocchi (Istituto per la Scienza e Tecnologia dei Plasmi)

Presentation materials