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It is often considered that a massive torus with solar mass or so surrounding a stellar-mass black hole may be a central engine of a gamma-ray burst. We study the properties of such massive accretion tori (or disks) based on the viscosity model. For surface density exceeding about 10^20 g cm^-2, which realizes when about a solar-mass material is contained within a disk with a size of 5 10⁶ cm, we find that (1) luminosity of photons is practically zero due to significant photon trapping, (2) neutrino cooling dominates over advective cooling, (3) pressure of degenerate electrons dominates over pressure of gas and photons, and (4) magnetic field strength exceeds the critical value of about 4 10^13 G, even if we take 0. 1 % of the equi-partition value. The possible observable quantum electrodynamical (QED) effects arising from super-critical fields are discussed. Most interestingly, photon splitting may occur, producing significant number of photons of energy below 511 keV, thereby possibly suppressing e^ pair creation.
Kohri et al. (Fri,) studied this question.