Evidence of the Dynamics of Relativistic Jet Launching in Quasars
  Hubble Space Telescope (HST) spectra of the extreme ultraviolet (EUV), the
optically thick emission from the innermost accretion flow onto the central
supermassive black hole, indicate that RLQs tend to be EUV weak compared to the
radio quiet quasars (RQQs); yet the remainder of the optically thick thermal
continuum is indistinguishable. The deficit of EUV emission in RLQs has a
straightforward interpretation as a missing or a suppressed innermost region of
local energy dissipation in the accretion flow. This article is an examination
of the evidence for a distribution of magnetic flux tubes in the innermost
accretion flow that results in magnetically arrested accretion (MAA) and
creates the EUV deficit. These same flux tubes and possibly the interior
magnetic flux that they encircle are the source of the jet power as well. In
the MAA scenario, islands of large scale magnetic vertical flux perforate the
innermost accretion flow of RLQs. The first prediction of the theory that is
supported by the HST data is that the strength of the (large scale poloidal
magnetic fields) jets in the MAA region is regulated by the ram pressure of the
accretion flow in the quasar environment. The second prediction that is
supported by the HST data is that the rotating magnetic islands remove energy
from the accretion flow as a Poynting flux dominated jet in proportion to the
square of the fraction of the EUV emitting gas that is displaced by these
islands.
