Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear waves in the terrestrial quasi-parallel foreshock   We study the applicability of the derivative nonlinear Schr\"{o}dinger (DNLS)
equation, for the evolution of high frequency nonlinear waves, observed at the
foreshock region of the terrestrial quasi-parallel bow shock. The use of a
pseudo-potential is elucidated and, in particular, the importance of canonical
representation in the correct interpretation of solutions in this formulation
is discussed. Numerical solutions of the DNLS equation are then compared
directly with the wave forms observed by Cluster spacecraft. Non harmonic slow
variations are filtered out by applying the empirical mode decomposition. We
find large amplitude nonlinear wave trains at frequencies above the proton
cyclotron frequency, followed in time by nearly harmonic low amplitude
fluctuations. The approximate phase speed of these nonlinear waves, indicated
by the parameters of numerical solutions, is of the order of the local
Alfv\'{e}n speed.

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The categories of this paper are: stat
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph