Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Rapid Modification of Neutron Star Surface Magnetic Field: A proposed
  mechanism for explaining Radio Emission State Changes in Pulsars   The radio emission in many pulsars show sudden changes, usually within a
period, that cannot be related to the steady state processes within the inner
acceleration region (IAR) above the polar cap. These changes are often
quasi-periodic in nature, where regular transitions between two or more stable
emission states are seen. The durations of these states show a wide variety
ranging from several seconds to hours at a time. There are strong, small scale
magnetic field structures and huge temperature gradients present at the polar
cap surface. We have considered several processes that can cause temporal
modifications of the local magnetic field structure and strength at the surface
of the polar cap. Using different magnetic field strengths and scales, and also
assuming realistic scales of the temperature gradients, the evolutionary
timescales of different phenomena affecting the surface magnetic field was
estimated. We find that the Hall drift results in faster changes in comparison
to both Ohmic decay and thermoelectric effects. A mechanism based on the
Partially Screened Gap (PSG) model of the IAR has been proposed, where the Hall
and thermoelectric oscillations perturb the polar cap magnetic field to alter
the sparking process in the PSG. This is likely to affect the observed radio
emission resulting in the observed state changes.

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The categories of this paper are: eess
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th