Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the nature of fast radio bursts   Scenario of formation of fast radio bursts (FRBs) is proposed. Just like
radio pulsars, sources of FRBs are magnetized neutron stars. Appearance of
strong electric field in a magnetosphere of a neutron star is associated with
close passage of a dense body near hot neutron star. For the repeating source
FRB 121102, which has been observed in four series of bursts, the period of
orbiting of the body is about 200 days. Thermal radiation from the surface of
the star (temperature is of the order of $ 10^8 \, K $) causes evaporation and
ionization of the matter of the dense body. Ionized gas (plasma) flows around
the magnetosphere of the neutron star with the velocity $ u \simeq 10^7 \, cm /
s $, and creates electric potential $ \psi_0 \simeq 10^{11} \, V $ in the polar
region of the magnetosphere. Electrons from the plasma flow are accelerated
toward the star, and gain Lorentz factor of $ \simeq 10 ^ 5 $. Thermal photons
moving toward precipitating electrons are scattered by them, and produce gamma
photons with energies of $ \simeq 10^5 \, m_e c^2 $. These gamma quanta produce
electron-positron pairs in collisions with thermal photons. The multiplicity,
the number of born pairs per one primary electron, is about $ 10^5 $. The
electron-positron plasma, produced in the polar region of magnetosphere,
accumulates in a narrow layer at a bottom of a potential well formed on one
side by a blocking potential $ \psi_0 $, and on the other side by pressure of
thermal radiation. The density of electron-positron plasma in the layer
increases with time, and after short time the layer becomes a mirror for
thermal radiation of the star. The thermal radiation in the polar region under
the layer is accumulated during time $ \simeq 500 \, s $, then the plasma layer
is ejected outside. The ejection is observed as burst of radio emission formed
by the flow of relativistic electron-positron plasma.

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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: patt-sol