Abstract:
The analytic perturbation procedure is divergent on the continuous spectrum near the threshold of creation of resonances. For scattering on Helmholtz resonator with a small opening we suggest a modified procedure which is convergent and permits to observe the creation of the resonance. The role of the first step ("jump-start") in that perturbation procedure is played by a solvable model of the resonator, which is completely fitted based on the resonance parameters
