Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coronal loops above an Active Region - observation versus model   We conducted a high-resolution numerical simulation of the solar corona above
a stable active region. The aim is to test the field-line braiding mechanism
for a sufficient coronal energy input. We also check the applicability of
scaling laws for coronal loop properties like the temperature and density. Our
3D-MHD model is driven from below by Hinode observations of the photosphere, in
particular a high-cadence time series of line-of-sight magnetograms and
horizontal velocities derived from the magnetograms. This driving applies
stress to the magnetic field and thereby delivers magnetic energy into the
corona, where currents are induced that heat the coronal plasma by Ohmic
dissipation. We compute synthetic coronal emission that we directly compare to
coronal observations of the same active region taken by Hinode. In the model,
coronal loops form at the same places as they are found in coronal
observations. Even the shapes of the synthetic loops in 3D space match those
found from a stereoscopic reconstruction based on STEREO spacecraft data. Some
loops turn out to be slightly over-dense in the model, as expected from
observations. This shows that the spatial and temporal distribution of the
Ohmic heating produces the structure and dynamics of a coronal loops system
close to what is found in observations.

23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph