Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Plasma planar filament instability and Alfven waves   Inhomogeneous plasmas filaments instabilities are investigated by using the
techniques of classical differential geometry of curves where Frenet torsion
and curvature describe completely the motion of curves. In our case the Frenet
frame changes in time and also depends upon the other coordinates taking into
account the inhomogeneity of the plasma. The exponential perturbation method so
commonly used to describe cosmological perturbatons is applied to
magnetohydrodynamic (MHD) plasma equations to find longitudinal modes
describing Alfven waves propagation modes describing plasma waves in the
medium. Stability is investigated in the imaginary axis of the spectra of
complex frequencies ${\omega}$ or $Im(\omega)\ne{0}$.

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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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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-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom