Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytical approximations to the core radius and energy of magnetic
  vortex in thin ferromagnetic disks   The energy of magnetic vortex core and its equilibrium radius in thin
circular cylinder were first presented by N.A. Usov and S.E. Peschany in 1994.
Yet, the magnetostatic function, entering the energy expression, is hard to
evaluate and approximate. In this communication precise and explicit analytical
approximations to this function (as well as equilibrium vortex core radius and
energy) are derived in terms of elementary functions. Also, several simplifying
approximations to the magnetic Hamiltonian and their impact on theoretical
stability of magnetic vortex state are discussed.

8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys