Speaker
Dr
Michela Gelfusa
(University of Rome "Tor Vergata")
Description
On JET the magnetic topology is normally derived from the code EFIT, which solves the Grad-Shafranov equation with constraints imposed by the available measurements, typically the pick-up coils. Both the code and the measurements are expected to perform worse during ELMs. To assess this hypothesis, various statistical indicators, based on the values of the residuals and their probability distribution, have been calculated. They all show that the quality of EFIT reconstructions is clearly better in absence of ELMs. The use of internal magnetic measurements, in particular the Faraday rotation measured by polarimetry, does not change significantly the results of the analysis. How the responsibility, for the lower quality of the reconstructions, is shared between the measurements and EFIT is a subject under investigation.
Primary author
Dr
Michela Gelfusa
(University of Rome "Tor Vergata")
Co-authors
Dr
Alexandru Boboc
(CCFE)
Dr
Andrea Murari
(Consorzio RFX)
Dr
Emmanuele Peluso
(University of Rome "La Sapienza")
Dr
Francesco Orsitto
(Enea Frascati)
Dr
Pasquale Gaudio
(University of Rome "Tor Vergata")
