Finiteamplitude longitudinal excitations in nuclear matter: A semiclassical treatment
Abstract
Finiteamplitude longitudinal collective excitations in spin and isospin saturated zerotemperature nuclear matter are investigated in the semiclassical limit, using a selfconsistent densitydependent interaction of the Skyrme type. There are no solitons and no shocks, only zerosound modes. Due to trapping of particles in the troughs of the selfconsistent potential, there is a relatively small maximum amplitude that a zerosound mode of a given wavelength can have. The theory of slowly modulated wavetrains of finiteamplitude zero sound is also developed. This theory shows that zero sound is stable, and that a modulation of finite extent ultimately breaks into two separated disturbances. In order to test the adequacy of nuclear hydrodynamics in the regime of large amplitudes, all calculations are performed twice, once exactly using the Vlasov equation, and once using a hydrodynamic approach. In the smallamplitude limit, hydrodynamics is semiquantitatively correct, while in the large amplitude region it is qualitatively incorrect. It incorrectly predicts the existence of zerosound solitons, and fails to take into account some of the most interesting new features which can arise, such as particle trapping, discontinuity of Fermi surface, and splitting of the Fermi sea into two disconnected parts.
 Publication:

Nuclear Physics A
 Pub Date:
 June 1981
 DOI:
 10.1016/03759474(81)904553
 Bibcode:
 1981NuPhA.363...69E