http://arxiv.org/abs/2305.09879
We point out the dominant importance of plasma injection effects for relativistic winds from pulsars and black holes. We demonstrate that outside the light cylinder the magnetically dominated outflows while sliding along the helical magnetic field move in fact nearly radially with very large Lorentz factors $\gamma_0 \gg 1 $, imprinted into the flow during pair production within the gaps. Only at larger distances, $r \geq \gamma_0 (c/\Omega)$, the MHD acceleration $\Gamma \propto r$ takes over. As a result, Blandford-Znajek (BZ) driven outflows would produce spine-brightened images, contrary to observations of the edge-brightened jet in M87. We conclude that M87 jet is not BZ-driven. Other implications include: (i) variability time scale of emission even from non-blazar AGNe like M87 and Cen A can be much shorter than the BH spin period; (ii) the model explains blazar-like phenomena in clearly non-aligned AGNe; (iii) in PIC simulations of pulsars’ and black holes’ magnetospheres with pair production, the pairs should be injected with large Lorentz factors – this would drastically change the resulting magnetospheric and inner-wind structure, if compared with pair injection at rest; (iv) the model resolves the problem of cyclotron absorption in the Crab pulsar wind.
M. Lyutikov and A. Ibrahim
Thu, 18 May 23
5/67
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