Vectorial electric field in type II superconductors
The calculations of losses in tokamak superconducting magnets require a knowledge of the vectorial law governing the electric field versus the current density and the magnetic induction. This law is well-known in only one particular case, that is when the current is perpendicular to the induction. It is proposed that the entire law be deduced only from the general equation of vortex motion and from the law connecting the electric field to the vortex momentum. In a first step, the vortex equilibrium state was studied and the way in which its limitation leads to the critical current. The comparison of theoretical predictions with measurements exhibited a discrepancy for small angles between induction and current. The force-free model invoked by some authors led to a result in contradiction with the measurements. Therefore, the law was completed here by considering the stability of the equilibrium, which introduced a second limitation for the current density. This phenomenon is similar to the instability encountered in the Hall effect for superconductors as well as in He II helicon modes. Theoretical prediction appears, now, in good agreement with the measurements. Lastly, the extension of the study to the non-zero temperature range appeared necessary in order to explain the observed electric field.
Bibliographic Reference: Paper presented: Physique en Herbe 92, Marseille (FR), July 5-10, 1992
Availability: Available from (1) as Paper EN 36975 ORA
Record Number: 199210874 / Last updated on: 1994-12-02
Original language: en
Available languages: en