  The cores of active galactic nuclei (AGN) are potential accelerators of
10-100 TeV cosmic rays, in turn producing high-energy neutrinos. This picture
was confirmed by the compelling evidence of a TeV neutrino signal from the
nearby active galaxy NGC 1068, leaving open the question of which is the site
and mechanism of cosmic ray acceleration. One candidate is the magnetized
turbulence surrounding the central supermassive black hole. Recent
particle-in-cell simulations of magnetized turbulence indicate that stochastic
cosmic ray acceleration is non-resonant, in contrast to the assumptions of
previous studies. We show that this has important consequences on a
self-consistent theory of neutrino production in the corona, leading to a more
rapid cosmic ray acceleration than previously considered. The turbulent
magnetic field fluctuations needed to explain the neutrino signal are
consistent with a magnetically powered corona. We find that strong turbulence,
with turbulent magnetic energy density higher than $1\%$ of the rest mass
energy density, naturally explains the normalization of the IceCube neutrino
flux, in addition to the neutrino spectral shape. Only a fraction of the
protons in the corona, which can be directly inferred from the neutrino signal,
are accelerated to high energies. Thus, in this framework, the neutrino signal
from NGC 1068 provides a testbed for particle acceleration in magnetized
turbulence.
