Published in "Astrophysical Jets", eds. D. Burgarella, M. Livio and C. P. O'Dea, 1993

ACCELERATION AND COLLIMATION MECHANISMS IN JETS

Roger Blandford


130-33 Caltech, Pasadena, CA 91125, USA

Abstract. Acceleration and collimation mechanisms for jets and bipolar outflows associated with active galactic nuclei, young stellar objects, X-ray binaries and perhaps cataclysmic variables are briefly described. The case for magnetic collimation by magnetic field attached to orbiting accretion disks is developed. It is argued that good collimation is not accomplished too close to the source of the power but is established over several decades of disk radius. Some critical observations and theoretical calculations are suggested.

Table of Contents

THE PROBLEM
Active Galactic Nuclei
Young Stellar Objects
X-ray Binaries
Cataclysmic Variables

NOZZLES, FUNNELS AND HOTPLATES
Nozzles
Funnels
Hotplates

MAGNETIZED ACCRETION DISKS
The Disk-Jet Connection
Magnetic jet collimation
Magnetic Accretion Disks
Magnetic Confinement of AGN Broad Emission Line Clouds
Flips and Flops

VARIATIONS ON THE THEME
Special Relativity
Black Hole MHD
Boundary Layers
Powers of Ten
Precession

THE FUTURE
What Theorists Would Like To Know From Observers
What Theorists Ought To Try To Understand

REFERENCES

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