To understand the dynamic, magnetic, and energetic
connection between the convectively unstable layers
below the visible surface of the Sun and the overlying
solar corona, we have developed a new three-dimensional
magnetohydrodynamic code capable of simultaneously
evolving a model convection zone and corona within a
single computational volume. As a first application
of this numerical model, we present a series of
simulations of the Quiet Sun in a domain that
encompasses both the upper convection zone and low
corona. We investigate whether the magnetic field
generated by a convective surface dynamo can account
for some of the observed properties of the Quiet Sun
atmosphere. We find that (1) it is possible to heat
a model corona to X-ray emitting temperatures with the
magnetic fields generated from a convective dynamo and
an empirically-based heating mechanism consistent with
the observed relationship between X-ray emission and
magnetic flux observed at the visible surface;
(2) within the limitations of our numerical models of
the Quiet Sun, resistive and viscous dissipation alone
are insufficient to maintain a hot corona; (3) the
Quiet Sun model chromosphere is a dynamic, non-force-free
layer that exhibits a temperature reversal in the
convective pattern in the relatively low-density layers
above the photosphere; (4) the majority of the unsigned
magnetic flux lies below the model photosphere in the
convectively unstable portion of the domain; (5)
horizontally-directed magnetic structures thread the
low atmosphere, often connecting relatively distant
concentrations of magnetic flux observed at the surface;
and (6) low-resolution photospheric magnetograms can
significantly underestimate the amount of unsigned
magnetic flux threading the Quiet Sun photosphere.
Authors: W. P. Abbett
Projects: None
Publication Status: ApJ (in press)
Last Modified: 2007-05-22 08:55