Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solar Magnetic Fields   This review provides an introduction to the generation and evolution of the
Sun's magnetic field, summarising both observational evidence and theoretical
models. The eleven year solar cycle, which is well known from a variety of
observed quantities, strongly supports the idea of a large-scale solar dynamo.
Current theoretical ideas on the location and mechanism of this dynamo are
presented.
  The solar cycle influences the behaviour of the global coronal magnetic field
and it is the eruptions of this field that can impact on the Earth's
environment. These global coronal variations can be modelled to a surprising
degree of accuracy. Recent high resolution observations of the Sun's magnetic
field in quiet regions, away from sunspots, show that there is a continual
evolution of a small-scale magnetic field, presumably produced by small-scale
dynamo action in the solar interior.
  Sunspots, a natural consequence of the large-scale dynamo, emerge, evolve and
disperse over a period of several days. Numerical simulations can help to
determine the physical processes governing the emergence of sunspots. We
discuss the interaction of these emerging fields with the pre-existing coronal
field, resulting in a variety of dynamic phenomena.

21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph