Nuclear matter in intense magnetic field and weak processes

We study the effect of magnetic field on the dominant neutrino emission pro cesses in neutron stars. The processes are first calculated for the case wh en the magnetic field does not exceed the critical value to confine electro ns to the lowest Landau state. We consider here magnetic fields up to simil ar to 10(19) Gauss. We find that fields of strength 10(15) - 10(16) Gauss h ave significant effect on the neutronization process, for the direct URCA p rocess the effect of the magnetic field becomes significant only at similar to 10(19) Gauss. In order to estimate the effect we derive the composition of cold nuclear matter at high densities and in beta equilibrium, a situat ion appropriate for neutron stars. The hadronic interactions are incorporat ed through the exchange of scalar and vector mesons in the framework of rel ativistic mean field theory. In addition the effects of anomalous magnetic moments of nucleons are also considered.