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Force-Free Electrodynamics of Pulsars

Andrei Gruzinov
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Abstract

We show that FFE (Force-Free Electrodynamics) describes pulsar magnetospheres -- even when radiation and particle wind power are comparable to the spin-down power. At the same time, we show that FFE is insufficient for calculating pulsar magnetospheres. This is because FFE admits a large family of stationary solutions with different currents flowing in the closed line region. To choose the actual solution one needs a model of current generation which goes beyond pure FFE. We calculate several FFE magnetospheres for the aligned rotator. The Poynting power of these solutions fills the range $c^{-3}μ^2Ω^4~< ~L~ <~ 0.67 c^{-3}μ^2Ω^4(c/ΩR_s)^2$, for angular velocity $Ω$ and magnetic field which is a pure dipole $μ$ on the surface of the star of radius $R_s$. Anomalous braking indices of young pulsars might be explained by currents flowing in the closed-line region.

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Andrei Gruzinov. 2006-04-17. Force-Free Electrodynamics of Pulsars. https://arxiv.org/abs/astro-ph/0604364

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