Analysis of linear branches in the I-V characteristics of Josephson junctions

Resistive branches have often been observed in the current-voltage characte ristics of long Josephson junctions. In the present paper we perform a syst ematic numerical analysis of the generation of these branches when an exter nal magnetic field is applied to the junctions. We show that the linear bra nches exist only over a limited voltage interval which is determined quanti tatively, We also clarify to what extent the linear branches can be attribu ted to flux-flow effects.