Flux creep phenomenon is a basic one for understanding many features of vortex behaviour in HTSC. Unfortunately, analytical results are available for a very limited number of flux creep problems. In most cases the only efficient tool to describe the vortex behavior is numerical simulations. This site presents videos obtained by flux creep simulations, namely, the time evolution of flux density, current density and electric field spatial distributions as well as magnetization hysteresis loops obtained under various external conditions.
Videos | (as animated GIF files) |
Complete set of movies for B(x), J(x), E(x) and M(Ba)
|
Comparative analysis |
For simulations we use Maxwell equation dB/dt = - dE/dx,
the electric field E = vB,
the velocity of the thermally activated vortex motion
v = vc exp[ -U(j) / kT ].
The current dependence of the pinning energy is usually taken
in logariphmic form,
U = Uc ln( j / jc ),
which leads to E ~ jn, with n = Uc / kT.
The relation between the current density and flux density is
j = dB/dx for the parallel geometry,
or the inverted Biot-Savart law
for the perpendicular geometry.
| Superconductivity Group at Oslo Univ. HTS Group at Ioffe Institute | Updated: 14.10.00, Maintained by D. Shantsev |