Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Virgin magnetization of a magnetically shielded superconductor wire:
  theory and experiment   On the basis of exact solutions to the London equation the magnetic moment of
a type II superconductor filament surrounded by a soft-magnet environment is
calculated and the procedure of extracting the superconductor contribution from
magnetic measurements is suggested. Comparison of theoretical results with
experiments on MgB_2/Fe wires allows estimation of the value of critical
current for the first magnetic flux penetration.

6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org