Related papers: Theory of magnetically powered jets
Hypersonic, highly collimated, mass outflows ({\it jets}) are a ubiquitous phenomena in astrophysics. While the character of the jets differ, many exhibit some form of quasi-periodic clumping indicating the jet source is episodic or {\it…
Collimated outflows (jets) appear to be a ubiquitous phenomenon associated with the accretion of material onto a compact object. Despite this ubiquity, many fundamental physics aspects of jets are still poorly understood and constrained.…
This is the fourth paper of our series of works studying winds from hot accretion flows around black holes. In the first two papers, we have shown the existence of strong winds in hot accretion flows using hydrodynamical and…
We review recent observational and theoretical results on the relationship between circumstellar accretion disks and jets in young stellar objects. We then present a theoretical framework that interprets jets as accretion-powered,…
Jets and outflows are commonly observed in young stellar objects (YSOs), yet their origins remain debated. Using 3D non-ideal magnetohydrodynamic (MHD) simulations of a circumstellar disk threaded by a large-scale open poloidal magnetic…
In this lecture I review the theory of magnetized accretion discs driving jets, with a focus on Young Stellar Objects (YSOs). I first introduce observational and theoretical arguments in favor of the ``disc wind'' paradigm. There, accretion…
The jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the…
We consider dynamo action under the combined influence of turbulence and large-scale shear in sheared jets. Shear can stretch turbulent magnetic field lines in such a way that even turbulent motions showing mirror symmetry become suitable…
We show that accretion disks with magnetic fields in them ought to make jets provided that their electrical conductivity prevents slippage and there is an ambient pressure in their surroundings. We study equilibria of highly wound magnetic…
Observations of gamma-ray-bursts and jets from active galactic nuclei reveal that the jet flow is characterized by a high radiative efficiency and that the dissipative mechanism must be a powerful accelerator of non-thermal particles.…
We review recent progress in the theory of jet production, with particular emphasis on the possibility of 1) powerful jets being produced in the first few seconds after collapse of a supernova core and 2) those jets being responsible for…
Highly collimated supersonic jets and less collimated outflows are observed to emerge from a wide variety of astrophysical objects. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (such as galactic…
Rotating magnetized compact objects and their accretion discs can generate strong toroidal magnetic fields driving highly magnetized plasmas into relativistic jets. Of significant concern, however, has been that a strong toroidal field in…
The structure of a relativistically hot, strongly magnetized jet is investigated at large distances from the source. Asymptotic equations are derived describing collimation and acceleration of the externally confined jet. Conditions are…
The magnetic fields and energy flows in an astronomical jet described by our earlier model are calculated in detail. Though the field distribution varies with the external pressure function p(z), it depends only weakly on the other boundary…
We consider the interaction between radiation, matter and a magnetic field in a compact, relativistic jet. The entrained matter accelerates outward as the jet breaks out of a star or other confining medium. In some circumstances, such as…
An axisymmetric MHD model is examined analytically to illustrate some key aspects of the physics of hot and magnetized outflows which originate in the near environment of a central gravitating body. By analyzing the asymptotical behaviour…
Magnetic field threading a black hole ergosphere is believed to play the key role in both driving the powerful relativistic jets observed in active galactic nuclei and extracting the rotational energy from a black hole via Blandford-Znajek…
I discuss three mutually-supportive notions or assumptions regarding jets and accretion. The first is magnetocentrifugal acceleration (MCA), the overwhelmingly favored mechanism for the production of jets in most steady accreting systems.…
An introduction is given to a meeting on the role of massive and stellar black holes in powering non-thermal activity in a rich variety of cosmic sources. Relevant properties of magnetized, spinning black holes are summarized and their…