The conditions under which nuclear collective modes couple to plasmon modes in asymmetric nuclear matter (ANM) neutralized by electrons, which is of interest for the study of neutron stars and supernovae, are investigated. The calculations were performed within a relativistic mean-field approach to nuclear matter, and the Coulomb field was included. We show that the coupling may be so strong that it affects the onset of the nuclear mode at low densities and may also affect its isovector/isoscalar character.

• Received 28 July 2006

DOI:https://doi.org/10.1103/PhysRevC.74.045802