Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Harmonic Generation from Laser-Irradiated Clusters   The harmonic emission from cluster nanoplasmas subject to short, intense
infrared laser pulses is analyzed by means of particle-in-cell simulations. A
pronounced resonant enhancement of the low-order harmonic yields is found when
the Mie plasma frequency of the ionizing and expanding cluster resonates with
the respective harmonic frequency. We show that a strong, nonlinear resonant
coupling of the cluster electrons with the laser field inhibits coherent
electron motion, suppressing the emitted radiation and restricting the spectrum
to only low-order harmonics. A pump-probe scheme is suggested to monitor the
ionization dynamics of the expanding clusters.

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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys