Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relaxation of writhe and twist of a bi-helical magnetic field   In the past few years suggestions have emerged that the solar magnetic field
might have a bi-helical component with oppositely polarized magnetic fields at
large and small scales, and that the shedding of such fields may be crucial for
the operation of the dynamo. It is shown that, if a bi-helical field is shed
into the solar wind, positive and negative contributions of the magnetic
helicity spectrum tend to mix and decay. Even in the absence of turbulence,
mixing and decay can occur on a time scale faster than the resistive one
provided the two signs of magnetic helicity originate from a single tube. In
the presence of turbulence, positively and negatively polarized contributions
mix rapidly in such a way that the ratio of magnetic helicity to magnetic
energy is largest both at the largest scale and in the dissipation range. In
absolute units the small scale excess of helical fields is however negligible.

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The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin