Jet Formation in Black Hole Accretion Systems II: Numerical Models
  In a companion theory paper, we presented a unified model of jet formation. We suggested that primarily two types of relativistic jets form near accreting black holes: a potentially ultrarelativistic Poynting-dominated jet and a Poynting-baryon jet. We showed that, for the collapsar model, the neutrino-driven enthalpy flux (classic fireball model) is probably dominated by the Blandford-Znajek energy flux, which predicts a jet Lorentz factor of $\Gamma\sim 100-1000$. We showed that radiatively inefficient AGN, such as M87, are synchrotron-cooling limited to $\Gamma\sim 2-10$. Radiatively efficient x-ray binaries, such as GRS1915+105, are Compton-drag limited to $\Gamma \lesssim 2$, but the jet may be destroyed by Compton drag. However, the Poynting-baryon jet is a collimated outflow with $\Gamma \sim 1-3$. Here we present general relativistic hydromagnetic simulations of black hole accretion with pair creation used to simulate jet formation in GRBs, AGN, and x-ray binaries. Our collapsar model shows the development of a patchy ``magnetic fireball'' with typically $\Gamma\sim 100-1000$ and a Gaussian structure. Temporal variability of the jet is dominated by toroidal field instabilities for $\gtrsim 10^2$ gravitational radii. A broader Poynting-baryon jet with $\Gamma\sim 1.5$ could contribute to a supernova. 
Jonathan C. McKinney