Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Parametrically excited surface waves in magnetic fluids: observation of
  domain structures   Observations of parametrically excited surface waves in a magnetic fluid are
presented. Under the influence of a magnetic field these waves have a
non--monotonic dispersion relation, which leads to a richer behavior than in
ordinary liquids. We report observation of three novel effects, namely:
  i) domain structures,
  ii) oscillating defects and
  iii) relaxational phase oscillations.

22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math