TP-07

Required Physics for Detaching Gamma Rays from Gamma Ray Bursters

Yoshiyuki Takahashi (UAH) and Toshiki Tajima (Lawrence Livermore National Laboratory)

Physical conditions required for explosion and detachment of gamma rays from an optically thick fireball are studied. It is shown that there are at least three conditions that allow relativistic detachment of gamma rays from a high-density fireball. It includes radiation pressure at the baryonic surface (30 $\sim$ 300 km) that exceeds 100 GeV in typical GRB's. Strong effects of non-linear QED are likely limiting thermal equilibrium of electron pairs beyond 10³³/cm³ owing to Pauli blocking and Landau-Pomeranchuk-Migdal interference, which leads overabundance of gamma rays and collective flow. It is also found that strong Alfven waves can mode-convert into EM waves which could accelerate electrons and positrons even in opaque fireball, allowing fast detachment of electron photon plasma from the source region. In addition, it is suggested how the phase transition of neutron matter into Quark Gluon Plasma helps increasing entropy of gamma rays as observed in excess of more than 35 times over the black body equilibrium.