Anisotropic kinetic pressure in ideal MHD and application to entropy production in neutrino-driven wind in supernovae

We study the stress tensor of electron in strong magnetic fields which are greater than the critical value Bc≃4.4×1013 G. We claim that such a strong magnetic field induces the anisotropic kinetic pressure term of electron in magnetohydrodynamic equations and can generate entropy in collisional quantum plasmas. We discuss its consequence to the neutrino-driven wind in core-collapse supernovae and argue that it can produce large entropy per baryon, S∼400kB. This mechanism might successfully account for the production of the heavy nuclei with mass numbers A=80–250 through the r-process nucleosynthesis.