  Coronal loops are the basic building block of the upper solar atmosphere.
Comprehending how these are energized, structured, and evolve is key to
understanding stellar coronae.
  Here we investigate how the energy to heat the loop is generated by
photospheric magneto-convection, transported into the upper atmosphere, and how
the internal structure of a coronal loop forms.
  In a 3D magnetohydrodynamics (MHD) model, we study an isolated coronal loop
rooted with both footpoints in a shallow layer within the convection zone using
the MURaM code. To resolve its internal structure, we limited the computational
domain to a rectangular box containing a single coronal loop as a straightened
magnetic flux tube. Field-aligned heat conduction, gray radiative transfer in
the photosphere and chromosphere, and optically thin radiative losses in the
corona were taken into account. The footpoints were allowed to interact
self-consistently with the granulation surrounding them.
  The loop is heated by a Poynting flux that is self-consistently generated
through small-scale motions within individual magnetic concentrations in the
photosphere. Turbulence develops in the upper layers of the atmosphere as a
response to the footpoint motions. We see little sign of heating by large-scale
braiding of magnetic flux tubes from different photospheric concentrations at a
given footpoint. The synthesized emission, as it would be observed by the
Atmospheric Imaging Assembly or the X-ray Telescope, reveals transient bright
strands that form in response to the heating events. Overall, our model roughly
reproduces the properties and evolution of the plasma as observed within
coronal loops.
  With this model we can build a coherent picture of how the energy flux to
heat the upper atmosphere is generated near the solar surface and how this
process drives and governs the heating and dynamics of a coronal loop.
