Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-01-08
Astronomy and Astrophysics
Astrophysics
15 pages, 13 figures. Accepted for publication, MNRAS
Scientific paper
10.1046/j.1365-8711.1999.02413.x
The axisymmetric 3-D MHD outflow of a cold plasma from a magnetized and rotating astrophysical object is numerically simulated with the purpose of investigating the outflow's magnetocentrifugal acceleration and eventual collimation. Gravity and thermal pressure are neglected while a split-monopole is used to describe the initial magnetic field configuration. It is found that the stationary final state depends critically on a single parameter alpha expressing the ratio of the corotating speed at the Alfven distance to the initial flow speed along the initial monopole-like magnetic fieldlines. Several angular velocity laws have been used for relativistic and nonrelativistic outflows. The acceleration of the flow is most effective at the equatorial plane and the terminal flow speed depends linearly on alpha. Significant flow collimation is found in nonrelativistic efficient magnetic rotators corresponding to relatively larger than 1 values of alpha while very weak collimation occurs in inefficient magnetic rotators with values of alpha smaller than about 1. Part of the flow around the rotation and magnetic axis is cylindrically collimated while the remaining part obtains radial asymptotics. The transverse radius of the jet is inversely proportional to alpha while the density in the jet grows linearly with alpha. For alpha greater than about 5 the magnitude of the flow in the jet remains below the fast MHD wave speed everywhere. In relativistic outflows, no collimation is found in the supersonic region for parameters typical for radio pulsars. All above results verify the main conclusions of general theoretical studies on the magnetic acceleration and collimation of outflows from magnetic rotators and extend previous numerical simulations to large stellar distances.
Bogovalov Sergei
Tsinganos Kanaris
No associations
LandOfFree
On the magnetic acceleration and collimation of astrophysical outflows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the magnetic acceleration and collimation of astrophysical outflows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the magnetic acceleration and collimation of astrophysical outflows will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-621734