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Paper: Magnetically Dominated Jets and Accretion Flows
Volume: 350, Blazar Variability Workshop II: Entering the GLAST Era
Page: 195
Authors: Meier, D.L.; Nakamura, M.
Abstract: I discuss two aspects of blazars and blazar-like sources that involve magnetically-dominated magnetohydrodynamic flows: Poynting-flux-dominated (PFD) jets and the magnetically-dominated accretion flows (MDAFs) that may create them. Three-dimensional simulations of Poynting jets show that they produce distinctive observational signatures: helical kinks or wiggles, with plasma flowing along the helical magnetic backbone. The instability that creates kinked jets is current-driven (related to the strong-field pinch), rather than Kelvin- Helmholtz driven, and saturates into laminar helical flow rather than turbulence. Identification of plasma blobs traveling along a helical pattern would be an indication that the helical kink instability is the main driver creating helical jets and that strong magnetic fields may be at work in such sources.
It is widely believed that jets in blazars are launched by magnetic processes in plasma that is accreting onto black holes. While numerical simulations of turbulent MHD accretion flows have begun to show some jet launching, the properties of these simulated jets and disks do not yet explain those in extensively-observed, jet-producing black hole systems. The galactic black hole candidates, in particular, provide a wealth of time-dependent information on how accretion flows behave when jets are, or are not, launched. Based on these observations, I have proposed a new type of accretion flow (the MDAF) that unites current theories of black hole accretion, magnetospheres, and jet-production. The model explains qualitatively and quantitatively the behavior of both disks and jets and has implications for black hole systems of any size, including blazars.
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