  Large-scale magnetic fields in the nuclear regions of protogalaxies can
promote the formation and early growth of supermassive black holes (SMBHs) by
direct collapse and magnetically boosted accretion. Turbulence associated with
gravitational infall and star formation can drive the rms field strength toward
equipartition with the mean gas kinetic energy; this field has a generic
tendency to self-organize into large, coherent structures. If the poloidal
component of the field (relative to the rotational axis of a star-forming disc)
becomes organized on scales $\lesssim r$ and attains an energy of order a few
percent of the turbulent energy in the disc, then dynamo effects are expected
to generate magnetic torques capable of increasing the inflow speed and
thickening the disc. The accretion flow can transport matter toward the center
of mass at a rate adequate to create and grow a massive direct-collapse black
hole (DCBH) seed and fuel the subsequent AGN at a high rate, without becoming
gravitationally unstable. Fragmentation and star formation are thus suppressed
and do not necessarily deplete the mass supply for the accretion flow, in
contrast to prevailing models for growing and fueling SMBHs through disc
accretion.
