Breaking of rotational symmetry of aligned rotators by hydromagnetic wave emission: How Saturn and pulsars may be linked.
Magnetic fields of planets and cool stars
D. J. Southwood
Imperial College
X. Jia University of Michigan USA
We show that whenever a rotating conducting object is embedded in a plasma environment not only is a twisted magnetic field structure created but also the field becomes kinked. The kinked structure means that even when the object itself is rotationally symmetric an asymmetric field structure is generated in the surrounding medium. Field aligned currents are an inevitable part of the symmetry breaking and accordingly pulsed radio emissions can be generated. The currents are carried by the hydromagnetic kink mode and should arise whenever a rotating body is exchanging angular momentum with its surroundings. Our results should have wide application in astrophysics. Possible applications include radio pulsing from aligned rotators such as pulsars or explain how a known aligned rotator like Saturn can emit regular pulsed radio emissions. We also propose that the mechanism we describe could be the source of twisted field structures commonly seen in plasma environments in solar, terrestrial, and magnetised and unmagnetised planetary environments.
09:00 - 10:30