Dynamical fluctuation of the order parameter and diamagnetism of superconductors. I. Dirty limit

Limiting ourselves to dirty superconductors, we study theoretically the fluctuation-induced diamagnetism above the superconducting transition. We find that the dynamical fluctuation is extremely important except in the immediate vicinity of the transition region i.e.,TT _c(H) orHH _c2(T), whereH _c2 is the upper critical field] and that this contribution does account for a large discrepancy between previous calculations and the recent experiment by Gollub, Beasley, and Tinkham.