New ideas for long Josephson junctions realistic devices simulation

In the paper, we consider the problem of numerical simulation of long Josephson Junction (JJ) devices. Our interest to the problem is motivated by need of erective parameters calculation of Flux Flow Oscillator (FFO). Practical FFOs have complicated structures and traditional model in form of simple perturbed sine-Gordon equation is inadequate because it doesn't capture important physical details. In this work, we evaluate variable coeficient 1D sine-Gordon equation and boundary conditions for this 1D equation starting from full 2D model of junction and 3D magnetic field problem for bias and control line currents. Then this 1D problem is solved numerically using implicit time stepping numerical procedure. As result program FFOSIM was developed. It is a general tool that allow calculations of critical current, I-V curves and other values. We present results of calculations of junctions inside microstrips where boundary conditions were evaluated using 3D magnetic field calculation program 3DMLSI.