  In Isliker et al. (2000b), an extended cellular automaton (X-CA) model for
solar flares was introduced. In this model, the interpretation of the model's
grid-variable is specified, and the magnetic field, the current, and an
approximation to the electric field are yielded, all in a way that is
consistent with Maxwell's and the MHD equations. Here, we reveal which relevant
plasma physical processes are implemented by the X-CA model and in what form,
and what global physical set-up is assumed by this model when it is in its
natural state (SOC). The basic results are: (1) On large-scales, all variables
show characteristic quasi-symmetries. (2) The global magnetic topology forms
either (i) closed magnetic field lines, or (ii) an arcade of field lines above
the bottom plane line, if the model is slightly modified. (3) In case of the
magnetic topology (ii), loading can be interpreted as if there were a plasma
which flows predominantly upwards, whereas in case of the magnetic topology
(i), as if there were a plasma flow expanding from the neutral line. (4) The
small-scale physics in the bursting phase represent localized diffusive
processes. (5) The local diffusivity usually has a value which is effectively
zero, and it turns locally to an anomalous value if a threshold is exceeded,
whereby diffusion dominates the quiet evolution (loading). (6) Flares
(avalanches) are accompanied by the appearance of localized, intense electric
fields. (7) In a variant on the X-CA model, the magnitude of the current is
used directly in the instability criterion. First results indicate that the SOC
state persists. (8) The current-dissipation during flares is spatially
fragmented into a large number of dissipative current-surfaces of varying
sizes, which show a highly dynamic temporal evolution.
