The Magnetic Field of Pure Superconductors with Non‐Isolated Flux Lines at Arbitrary Temperature

The magnetic field distribution of pure type‐II superconductors with small magnetization is derived from the non‐local version of Gorkov's theory. At zero temperature Delrieu's result is reproduced: at the vortex centre the field shows a cusp and exceeds the external field. The form factors have alternating sign and decrease only as K −3 . At larger magnetization all form factors become positive. At T = 0, even close to Hc 2 , a gap function is expected deviating considerably from the H c2 ‐solution. This means a pronounced narrowing of the vortex core at low temperatures.