Name of the Speaker(s): Dr S. G. Lucek
Institution: Imperial College (United Kingdom)
Title of the communication: Magnetohydrodynamic Jet formation
Preliminary abstract (12 lines max.): (please see attatched note for more
details)
2 and 3 D numerical solutions for the time-dependent, ideal MHD, equations
suggest that jets may be readily formed by a number of different processes. Two
related processes are examined here, i) the rotation of an accretion disk in a
magnetic field and ii) the pinching of a wind from a stationary disk by an
azimuthal magnetic field. In the first case, the accretion disk loses angular
momentum and falls into a gravitational well, building up the pressure near the
centre of the well, which ejects a jet along the rotation axis. The jet is
collimated partly by hydrodynamic funnelling and partly by the axial component
of the magnetic field, which is compressed and amplified by the infall of the
disk. In the second case, idealised calculations of the generic problem of
collimation by an azimuthal field indicate that, whilst a jet is readily
formed, it is prone to large m=1 (kink) instabilities which disrupt the jet.