  A system of multiple open magnetic flux tubes spanning the solar photosphere
and lower corona is modelled analytically, within a realistic stratified
atmosphere subject to solar gravity. This extends results for a single magnetic
flux tube in magnetohydrostatic equilibrium, described in Gent et al. (MNRAS,
435, 689, 2013). Self-similar magnetic flux tubes are combined to form magnetic
structures, which are consistent with high-resolution observations. The
observational evidence supports the existence of strands of open flux tubes and
loops persisting in a relatively steady state. Self-similar magnetic flux
tubes, for which an analytic solution to the plasma density and pressure
distribution is possible, are combined. We calculate the appropriate balancing
forces, applying to the equations of momentum and energy conservation to
preserve equilibrium.
  Multiplex flux tube configurations are observed to remain relatively stable
for up to a day or more, and it is our aim to apply our model as the background
condition for numerical studies of energy transport mechanisms from the solar
surface to the corona. We apply magnetic field strength, plasma density,
pressure and temperature distributions consistent with observational and
theoretical estimates for the lower solar atmosphere. Although each flux tube
is identical in construction apart from the location of the radial axis,
combinations can be applied to generate a non-axisymmetric magnetic field with
multiple non-uniform flux tubes. This is a considerable step forward in
modelling the realistic magnetized three-dimensional equilibria of the solar
atmosphere.
