  We investigate the difference in the spatial distribution of the energy input
for parametrizations of different mechanisms to heat the corona of the Sun and
possible impacts on the coronal emission. We use a 3D MHD model of a solar
active region as a reference and compare the Ohmic-type heating in this model
to parametrizations for alternating current (AC) and direct current (DC)
heating models, in particular, we use Alfven wave and MHD turbulence heating.
We extract the quantities needed for these two parametrizations from the
reference model and investigate the spatial distribution of the heat input in
all three cases, globally and along individual field lines. To study
differences in the resulting coronal emission we employ 1D loop models with a
prescribed heat input based on the heating rate we extracted along a bundle of
field lines. On average, all heating implementations show a roughly drop of the
heating rate with height. This also holds for individual field lines. While all
mechanism show a concentration of the energy input towards the low parts of the
atmosphere, for individual field lines the concentration towards the footpoints
is much stronger for the DC mechanisms than for the Alfven wave AC case. In
contrast, the AC model gives a stronger concentration of the emission towards
the footpoints. This is because the more homogeneous distribution of the energy
input leads to higher coronal temperatures and a more extended transition
region. The significant difference in the concentration of the heat input
towards the foot points for the AC and DC mechanisms, and the pointed
difference in the spatial distribution of the coronal emission for these cases
shows that the two mechanisms should be discriminable by observations. Before
drawing final conclusions, these parametrizations should be implemented in new
3D models in a more self-consistent way.
