Critical current in a long Josephson contact in an external magnetic field at strong pinning

Possible current distributions upon the passage of current through a periodically modulated long Josephson contact in an external magnetic field are analyzed. The case in which the pinning parameter is larger than its critical value is considered. It is shown that for any value of the external magnetic field, the maximal persistent current is determined exclusively by the contact length and is independent of the field. The approach used in calculations is based on analysis of a continuous variation of the current configuration in the direction of the decrease in the Gibbs potential.