FLUXON-FLUXON COLLISION TESTING BY A DISSIPATIVE SPOT

Fluxon collisions have recently been successfully imaged by a focused electron beam [A. Laub et nl., Phys. Rev. Lett. 75, 1372 (1995)]. This report presents numerical and analytical calculations of the effect o f a beam-induced dissipative spot on a fluxon-fluxon collision in alon g Josephson junction. In contrast to the fluxon-antifluxon collision, the energy loss for the colliding fluxons of the same polarity is mini mal at the collision point. Good accord between analytical and numeric al results is found. Presented calculations are relevant for interpret ation of the low temperature scanning electron microscopy experiments on fluxon imaging in long Josephson junctions.