<FONT face=Verdana>A one-dimensional Poincaré map for the forward traveling voltage wave at the left end of Josephson junction electromagnetic system with lossless transmission line is derived. The stability at fixed point of the map is analyzed based on nonlinear dynamics theory. The bifurcation diagrams with voltage reflex coefficient as parameter are obtained through numerical computation and the dynamic evolutive process of the system is analyzed in detail. Numerical results show that under certain parametric condition complex nonlinear dynamical behaviors exist in the electromagnetic system

such as bifurcation

chaos

coexisting periodic attractors

coexisting chaotic attractors

and coexisting periodic-chaotic attractors.