Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear vertical oscillations of a particle in a sheath of a rf
  discharge   A new simple method to measure the spatial distribution of the electric field
in the plasma sheath is proposed. The method is based on the experimental
investigation of vertical oscillations of a single particle in the sheath of a
low-pressure radio-frequency discharge. It is shown that the oscillations
become strongly nonlinear and secondary harmonics are generated as the
amplitude increases. The theory of anharmonic oscillations provides a good
qualitative description of the data and gives estimates for the first two
anharmonic terms in an expansion of the sheath potential around the particle
equilibrium.

27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs