  Observations of the FR I radio galaxy Centaurus A in radio, X-ray and
gamma-ray bands provide evidence for lepton acceleration up to several TeV and
clues about hadron acceleration to tens of EeV. Synthesising the available
observational constraints on the physical conditions and particle content in
the jets, inner lobes and giant lobes of Centaurus A, we aim to evaluate its
feasibility as an ultra-high-energy cosmic-ray source. We apply several methods
of determining jet power and affirm the consistency of various power estimates
of ~ 1 x 10^43 erg s^-1. Employing scaling relations based on previous results
for 3C 31, we estimate particle number densities in the jets, encompassing
available radio through X-ray observations. Our model is compatible with the
jets ingesting ~ 3 x 10^21 g s^-1 of matter via external entrainment from hot
gas and ~ 7 x 10^22 g s^-1 via internal entrainment from jet-contained stars.
This leads to an imbalance between the internal lobe pressure available from
radiating particles and magnetic field, and our derived external pressure.
Based on knowledge of the external environments of other FR I sources, we
estimate the thermal pressure in the giant lobes as 1.5 x 10^-12 dyn cm^-2,
from which we deduce a lower limit to the temperature of ~ 1.6 x 10^8 K. Using
dynamical and buoyancy arguments, we infer ~ 440-645 Myr and ~ 560 Myr as the
sound-crossing and buoyancy ages of the giant lobes respectively, inconsistent
with their spectral ages. We re-investigate the feasibility of particle
acceleration via stochastic processes in the lobes, placing new constraints on
the energetics and on turbulent input to the lobes. The same 'very hot'
temperatures that allow self-consistency between the entrainment calculations
and the missing pressure also allow stochastic UHECR acceleration models to
work.
