TY - JOUR
T1 - PULSAR MAGNETOSPHERES
T2 - Beyond the FLAT SPACETIME DIPOLE
AU - Gralla, Samuel E.
AU - Lupsasca, Alexandru
AU - Philippov, Alexander
N1 - Funding Information:
This research was supported by the NASA Earth and Space Science Fellowship Program (grant NNX15AT50H to A.P.), as well as NSF grants 1205550 to Harvard University and 1506027 to the University of Arizona. The simulations presented in this paper used computational resources supported by the PICSciE-OIT High Performance Computing Center and Visualization Laboratory.
Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/12/20
Y1 - 2016/12/20
N2 - Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields will have a significant nondipolar component. We introduce a general analytical method for studying the axisymmetric force-free magnetosphere of a slowly rotating star of arbitrary magnetic field, mass, radius, and moment of inertia, including all the effects of general relativity. We confirm that spacelike current is generically present in the polar caps (suggesting a pair production region), irrespective of the stellar magnetic field. We show that general relativity introduces a ∼60% correction to the formula for the dipolar component of the surface magnetic field inferred from spindown. Finally, we show that the location and shape of the polar caps can be modified dramatically by even modestly strong higher moments. This can affect emission processes occurring near the star and may help explain the modified beam characteristics of millisecond pulsars.
AB - Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields will have a significant nondipolar component. We introduce a general analytical method for studying the axisymmetric force-free magnetosphere of a slowly rotating star of arbitrary magnetic field, mass, radius, and moment of inertia, including all the effects of general relativity. We confirm that spacelike current is generically present in the polar caps (suggesting a pair production region), irrespective of the stellar magnetic field. We show that general relativity introduces a ∼60% correction to the formula for the dipolar component of the surface magnetic field inferred from spindown. Finally, we show that the location and shape of the polar caps can be modified dramatically by even modestly strong higher moments. This can affect emission processes occurring near the star and may help explain the modified beam characteristics of millisecond pulsars.
KW - magnetic fields
KW - plasmas
KW - pulsars: general
KW - stars: rotation
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U2 - 10.3847/1538-4357/833/2/258
DO - 10.3847/1538-4357/833/2/258
M3 - Article
AN - SCOPUS:85007623441
SN - 0004-637X
VL - 833
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 258
ER -