Advances in Chromatography, Vol. 7, edited by J. Calvin Giddings and R. A. Keller, Marcel Dekker Inc., New York, 1968, 313 pages, price $ 15.75.

Thermomagnetic vortex transport: Transport entropy revisited

“…In current theories [7][8][9][10][11] the transport entropy S d is attributed to the electromagnetic energy of superconducting currents F em (for F em in various models see also [12,13]). Moreover, according to all theories, the contribution of supercurrents, S em d , significantly prevails over a contribution of the core, S core d .…”

“…In refs. [7][8][9] the supercurrent-related entropy S em d was calculated in the Ginzburg-Landau (GL) formalism. In [10] S em d was obtained in the London model, which was developed for extreme type-II superconductors (ξ λ), where cores are treated as point singularities and S core d is absent at all.…”

“…Thus, according to the current theories [7][8][9][10][11], the superconducting currents around a core provide the main contribution to the transport entropy, i.e. the supercurrents create the net thermal force in the Nernst effect and also transfer the heat in the Ettingshausen effect.…”

“…If the entropy S d moves from the area with the temperature T to the area with the temperature T − ∆T , the ratio of the work produced by thermal force, f th • ∆r, to the thermal energy, T S d , is given by the Carnot efficiency ∆T /T . Therefore, the thermal force may be expressed as f th = −S d ∇T [5][6][7][8]. The thermal force f th leads to the vortex motion with the velocity v T = f th /η, where η is the viscosity coefficient.…”

“…However, after many years of extensive theoretical and experimental research, the physical sense of S d and its relation with ordinary entropy are still unclear [5,6]. Calculating S d , the theoretical works [7][8][9][10][11] neglected the core contribution and restricted themselves with F em only. In his pioneering paper, [7], Stephen considered thermomagnetic vortex transport near H c1 , where an interaction between vortices can be neglected.…”