SIMBAD references

It is known that vacuum polarization can modify the photon propagation modes in the atmospheric plasma of a strongly magnetized neutron star. A resonance occurs when the effect of vacuum polarization on the photon modes balances that of the plasma. We show that a photon (with energy E≳ a few keV) propagating outward in the atmosphere can convert from one polarization mode into another as it traverses the resonant density, ρ_res≃Y^–1_eη^–2(B/10¹⁴G)²(E/1keV)² g.cm^–3, where Y_e is the electron fraction and η∼1 is a slowly varying function of the magnetic field B. The physics of this mode conversion is analogous to the Mikheyev-Smirnov-Wolfenstein mechanism for neutrino oscillation. Because the two photon modes have vastly different opacities in the atmosphere, this vacuum-induced mode conversion can significantly affect radiative transport and surface emission from strongly magnetized neutron stars.