SNIC
SUPR
SNIC SUPR
Expulsion of Magnetic Fields From Bulk Type II Super-conducting Materials during Phase Transition from normal to super-conducting state
Dnr:

SNIC 2017/7-159

Type:

SNAC Small

Principal Investigator:

Anirban Bhattacharyya

Affiliation:

Uppsala universitet

Start Date:

2017-10-10

End Date:

2018-11-01

Primary Classification:

10306: Accelerator Physics and Instrumentation

Webpage:

Allocation

Abstract

During cavity testing exercise at FREIA for the European Spallation Source (ESS) we have observed the effect of the rate of cooling of the superconducting material Niobium on the cavity quality factor. This observation indicates that the rate of cooling has direct effect on the expulsion of magnetic fields from the bulk superconducting material. This phenomenon can be explained from first principles using the theory of super-conductors developed by Ginzburg and Landau. In this computational exercise we solve the time dependent Ginzburg-Landau (GL) equations with various temperature gradients in the material as well as various cooling rates in time to explain the phenomenon of flux trapping from first principles, an exercise which has never been done before and as such is a direct explanation of experimental results seen at FREIA and Argon National Laboratory.