Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Space charge and collective oscillation of ion cloud in a linear Paul
  trap   The presence of charged particles in an ion trap modifies the harmonic
trapping potential in which they are trapped, leading to observed shifts in
secular frequency as well as appearance of collective oscillation. In a linear
trap geometry, both of these effects have been observed under different
trapping conditions using narrow non-linear resonance and external excitation.
The observations have been modeled with minimal fitting parameter showing good
agreement with results obtained. The space charge in our experiment plays an
important role in terms of criticality of the onset of collective oscillation.

18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph