Physics of strongly magnetized neutron stars

There has recently been growing evidence for the existence of neutron stars possessing magnetic fields with strengths that exceed the quantum critical field strength of $4.4 \\times 10^{13}$ G, at which the cyclotron energy equals the electron rest mass. Such evidence has been provided by new discoveries of radio pulsars having very high spin-down rates and by observations of bursting gamma-ray sources termed magnetars. This article will discuss the exotic physics of this high-field regime, where a new array of processes becomes possible and even dominant, and where familiar processes acquire unusual properties. We review the physical processes that are important in neutron star interiors and magnetospheres,…