Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-02-20
Astrophys.J.657:967-993,2007
Astronomy and Astrophysics
Astrophysics
70 pages, 14 figures, accepted to ApJ
Scientific paper
10.1086/508917
We develop a theoretical model that explains the formation of hot coronae around strongly magnetized neutron stars -- magnetars. The starquakes of a magnetar shear its external magnetic field, which becomes non-potential and is threaded by an electric current. Once twisted, the magnetosphere cannot untwist immediately because of its self-induction. The self-induction electric field lifts particles from the stellar surface, accelerates them, and initiates avalanches of pair creation in the magnetosphere. The created plasma corona maintains the electric current demanded by curl(B) and regulates the self-induction e.m.f. by screening. This corona persists in dynamic equilibrium: it is continually lost to the stellar surface on the light-crossing time of 10^{-4} s and replenished with new particles. In essence, the twisted magnetosphere acts as an accelerator that converts the toroidal field energy to particle kinetic energy. Using a direct numerical experiment, we show that the corona self-organizes quickly (on a millisecond timescale) into a quasi-steady state, with voltage ~1 GeV along the magnetic lines. The heating rate of the corona is ~10^{36} erg/s, in agreement with the observed persistent, high-energy output of magnetars. We deduce that a static twist that is suddenly implanted into the magnetosphere will decay on a timescale of 1-10 yrs. The particles accelerated in the corona impact the solid crust, knock out protons, and regulate the column density of the hydrostatic atmosphere of the star. The transition layer between the atmosphere and the corona is the likely source of the observed 100-keV emission from magnetars. The corona emits curvature radiation and can supply the observed IR-optical luminosity. (Abridged)
Beloborodov Andrei M.
Thompson Christopher
No associations
LandOfFree
Corona of Magnetars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Corona of Magnetars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Corona of Magnetars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-520130