Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The St{\o}rmer problem for an aligned rotator   The effective potential energy of the particles in the field of rotating
uniformly magnetized celestial body is investigated. The axis of rotation
coincides with the axis of the magnetic field. Electromagnetic field of the
body is composed of a dipole magnetic and quadrupole electric fields. The
geometry of the trapping regions is studied as a function of the magnetic field
magnitude and the rotation speed of the body. Examples of the potential energy
topology for different values of these parameters are given. The main
difference from the classical St{\o}rmer problem is that the single toroidal
trapping region predicted by St{\o}rmer is divided into equatorial and
off-equatorial trapping regions. Applicability of the idealized model of a
rotating uniformly magnetized sphere with a vacuum magnetosphere to real
celestial bodies is discussed.

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The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci