Low Temperature Physics: 34, 571 (2008); https://doi.org/10.1063/1.2957010 (4 pages)
On phase, action and canonical conservation laws in kinematic-wave theory
Gerard A. Maugin
Universitй Pierre et Marie Curie (Paris-6), Institut Jean Le Rond d'Alembert UMR 7190 CNRS, Case 162, 4 place Jussieu, 75252 Paris Cedex 05, France
Received November 26, 2007
Canonical equations of energy and momentum are constructed in the kinematic-wave theory of waves in a continuum. This is done in analogy with what is achieved in nonlinear continuum mechanics. The starting point is a generalized balance of wave action. The standard formulas are recovered when the system follows from the averaged-Lagrangian variational formulation of Whitham.
PACS: 75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.);
Key words: waves, phase, action, momentum, conservation laws.