Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of oscillatory radial electric field relaxation in a helical
  plasma   Measurements of the relaxation of a zonal electrostatic potential
perturbation in a non-axisymmetric magnetically confined plasma are presented.
A sudden perturbation of the plasma equilibrium is induced by the injection of
a cryogenic hydrogen pellet in the TJ-II stellarator, which is observed to be
followed by a damped oscillation in the electrostatic potential. The waveform
of the relaxation is consistent with theoretical calculations of zonal
potential relaxation in a non-axisymmetric magnetic geometry. The turbulent
transport properties of a magnetic confinement configuration are expected to
depend on the features of the collisionless damping of zonal flows, of which
the present letter is the first direct observation.

7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph