Limit cycles in piecewise smooth perturbations of a quartic isochronous center

Abstract

This article concerns the bifurcation of limit cycles from a quartic integrable and non-Hamiltonian system. By using the first order averaging method and some mathematical technique on estimating the number of the zeros, we show that under a class of piecewise smooth quartic perturbations, seven is a lower and twelve an upper bound for the maximum number of limit cycles bifurcating from the unperturbed quartic isochronous center.