Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The structure of current layers and degree of field line braiding in
  coronal loops   One proposed resolution to the long-standing problem of solar coronal heating
involves the buildup of magnetic energy in the corona due to turbulent motions
at the photosphere that braid the coronal field, and the subsequent release of
this energy via magnetic reconnection. In this paper the ideal relaxation of
braided magnetic fields modelling solar coronal loops is followed. A sequence
of loops with increasing braid complexity is considered, with the aim of
understanding how this complexity influences the development of small scales in
the magnetic field, and thus the energy available for heating. It is
demonstrated that the ideally accessible force-free equilibrium for these
braided fields contains current layers of finite thickness. It is further shown
that for any such braided field, if a force-free equilibrium exists then it
should contain current layers whose thickness is determined by length scales in
the field line mapping. The thickness and intensity of the current layers
follow scaling laws, and this allows us to extrapolate beyond the numerically
accessible parameter regime and to place an upper bound on the braid complexity
possible at coronal plasma parameters. At this threshold level the braided loop
contains $10^{26}$--$10^{28}{\rm ergs}$ of available free magnetic energy, more
than sufficient for a large nanoflare.

12
The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
2
The categories of this paper are: math
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph