Interpretation of runaway electron synchrotron and bremsstrahlung images
Preprint, 2018

The crescent spot shape observed in DIII-D runaway electron synchrotron radiation images is shown to result from the high degree of anisotropy in the emitted radiation, the finite spectral range of the camera and the distribution of runaways. The finite spectral camera range is found to be particularly important, as the radiation from the high-field side can be stronger by a factor 106 than the radiation from the low-field side in DIII-D. By combining a kinetic model of the runaway dynamics with a synthetic synchrotron diagnostic we see that physical processes not described by the kinetic model (such as radial transport) are likely to be limiting the energy of the runaways. We show that a population of runaways with lower dominant energies and larger pitch-angles than those predicted by the kinetic model provide a better match to the synchrotron measurements. Using a new synthetic bremsstrahlung diagnostic we also simulate the view of the Gamma Ray Imager (GRI) diagnostic used at DIII-D to resolve the spatial distribution of runaway-generated bremsstrahlung.

Författare

Mathias Hoppe

Chalmers, Fysik, Subatomär fysik och plasmafysik

Ola Embréus

Chalmers, Fysik, Subatomär fysik och plasmafysik

C. Paz-Soldan

R. A. Moyer

Tünde Fülöp

Chalmers, Fysik, Subatomär fysik och plasmafysik

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Fundament

Grundläggande vetenskaper

Ämneskategorier

Fusion, plasma och rymdfysik