Peakons and periodic cusp waves in a generalized Camassa-Holm equation. (English) Zbl 1021.35086

Qian, Tifei; Tang, Minying

Chaos Solitons Fractals 12, No. 7, 1347-1360 (2001).

Summary: We study the peakons and the periodic cusp wave solutions of the equation \[ u_t + 2ku_x-u_{xxt} +auu_x = 2u_xu_{xx} + uu_{xxx}, \] with \(a, k\in\mathbb{R}\), which we will call the generalized Camassa-Holm equation, or simply the GCH equation, for \(a = 3\) it is the CH Camassa-Holm equation. Camassa and Holm showed that the CH equation has a class of new solitary wave solutions called “peakons”.
Using the bifurcation method of the phase plane, we first construct peakons and show that \(a = 3\) is the peakon bifurcation parameter value for the GCH equation. Then we construct some smooth periodic wave solutions, periodic cusp wave solutions, and oscillatory solitary wave solutions, and show their convergence when either the parameter \(a\) or the wave speed \(c\) varies. We also illustrate how to identify the existence of peakons and periodic cusp waves from the phase portraits. It seems that the GCH equation is a good example to understand the relationships among peakons, periodic cusp waves, oscillatory solitary waves and smooth periodic wave solutions.

MSC:

35Q35	PDEs in connection with fluid mechanics
35B10	Periodic solutions to PDEs
37K40	Soliton theory, asymptotic behavior of solutions of infinite-dimensional Hamiltonian systems

Keywords:

Camassa-Holm equation; peakons; peakon bifurcation parameter value; smooth periodic wave; periodic cusp wave; oscillatory solitary wave

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