Department of Physics, Faculty of Science, Nagoya University, Nagoya 464-01, Japan
(Received April 27, 1991; Accepted November 1, 1991)
Keywords: Magnetic Flux, High Temperature Superconductors
Abstract. This lecture note is concerned with some recent developments in our understanding of the dynamics of magnetic flux structures in type-II superconductors. Especially, we focus on the recently observed peculiar behavior of the magnetic flux states in high temperature superconductors. Although the theoretical position is still somewhat unclear, it is worth for further progress that we review the present theoretical attempts to explain them, including our recent results.