Protoneutron Star Winds

Neutrino-driven winds are thought to accompany the Kelvin-Helmholtz cooling phase of nascent protoneutron stars in the first seconds after a core-collapse supernova. These outflows are a likely candidate as the astrophysical site for rapid neutron-capture nucleosynthesis (the r-process). In this chapter we review the physics of protoneutron star winds and assess their potential as a site for the production of the heavy r-process nuclides. We show that spherical transonic protoneutron star winds do not produce robust $r$-process nucleosynthesis for `canonical' neutron stars with gravitational masses of 1.4 M_sun and coordinate radii of 10 km. We further speculate on and review some aspects of neutrino-driven winds from protoneutron stars with strong magnetic fields.