  The effects of an imposed, axial magnetic field $B_{z0}$ on hydrodynamics and
energetic electrons in inertial confinement fusion (ICF) indirect-drive
hohlraums are studied. We present simulations from the radiation-hydrodynamics
code HYDRA of a low-adiabat ignition design for the National Ignition Facility
(NIF), with and without $B_{z0}=70$ Tesla. The field's main hydrodynamic effect
is to significantly reduce electron thermal conduction perpendicular to the
field. This results in hotter and less dense plasma on the equator between the
capsule and hohlraum wall. The inner laser beams experience less inverse
bremsstrahlung absorption before reaching the wall. The x-ray drive is thus
stronger from the equator with the imposed field. We study superthermal, or
"hot," electron dynamics with the particle-in-cell code ZUMA, using plasma
conditions from HYDRA. During the early-time laser picket, hot electrons based
on two-plasmon decay in the laser entrance hole (Regan et al., Phys. Plasmas
2010) are guided to the capsule by a 70 T field. 12x more energy deposits in
the deuterium-tritium (DT) fuel. For plasma conditions early in peak laser
power, we present mono-energetic test-case studies with ZUMA, as well as
sources based on inner-beam stimulated Raman scattering. The effect of the
field on DT deposition depends strongly on the source location, namely whether
hot electrons are generated on field lines that connect to the capsule.
