Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Twisting, reconnecting magnetospheres and magnetar spindown   We present the first simulations of evolving, strongly twisted magnetar
magnetospheres. Slow shearing of the magnetar crust is seen to lead to a series
of magnetospheric expansion and reconnection events, corresponding to X-ray
flares and bursts. The axisymmetric simulations include rotation of the neutron
star and the magnetic wind through the light cylinder. We study how the
increasing twist affects the spindown rate of the star, finding that a dramatic
increase in spindown occurs. Particularly spectacular are explosive events
caused by the sudden opening of large amounts of overtwisted magnetic flux,
which may be associated with the observed giant flares. These events are
accompanied by a short period of ultra-strong spindown, resulting in an abrupt
increase in spin period, such as was observed in the giant flare of SGR
1900+14.

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The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin