Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strong reduction of ac losses in a superconductor strip located between
  superconducting ground plates   The problem of calculating the ac losses in a superconductor strip with a
transport current placed inside superconducting environments is studied
analytically in the frame of the critical state model. Exact results obtained
by the method of images for the commonly employed flat ground plates are used
to derive power losses and, consequently, the nonlinear resistance depending on
the ac frequency, current amplitude and the distance to the ground plates. The
resistance is strongly reduced when the distance between the strip and the
shields becomes small.

20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th