Universal description of the resonant facilitation of the inter-separatrix chaos onset

We have developed a universal asymptotic description of the strong resonance-mediated facilitation of the onset of the inter-separatrix chaotic transport (IST) - a remarkable phenomenon discovered a decade ago and being relevant to a vast variety of systems. Apart from a fundamental importance, our results are of a big practical use: our explicit formulas allow us to immediately predict a coarse-grained line in the parameters plane marking the facilitated onset of the IST while computer simulations, conventionally used to accomplish this task, take a large time. We illustrate the efficiency of our general results at the example of the cross-jet transport in a meandering flow.