Astronomy and Astrophysics – Astrophysics
Scientific paper
Nov 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...278..561h&link_type=abstract
Astronomy and Astrophysics (ISSN 0004-6361), vol. 278, no. 2, p. 561-568
Astronomy and Astrophysics
Astrophysics
26
Dynamo Theory, Interstellar Magnetic Fields, Interstellar Matter, Magnetohydrodynamics, Molecular Clouds, Spiral Galaxies, Coriolis Effect, Magnetic Field Reconnection, Thermal Diffusivity
Scientific paper
Concentrating on the role of the Parker instability, we consider an intrinsic instability of the magnetic field as a possible origin of the alpha-effect taking part in the dynamo action. We examine the possibility that the magnetic field is concentrated in braked, isolated flux tubes extended between molecular clouds. We estimate that the ionized gas moving along the tube of the total length 100 pc, the mean intercloud distance, acquires due to Coriolis force the cyclonic velocity approx. = 1.5 km/s. The balance of the drag force and the buoyancy force acting on the rising flux tubes establishes the characteristic velocity of rise approx. = 1 km/s. We point out that these slow flux tube velocities, can lead to the comparatively small diffusivity coeffcient etaT approx. = 0.06 x 1026 sq cm/s. The estimation of helicity in this model gives alpha approx. = 0.6 km/s. This result leads to the conclusion that the dynamo number D = Ralpha Romega can be increased even by a factor of 100 with respect to the standard model.
Hanasz Michal
Lesch Harald
No associations
LandOfFree
Magnetic buoyancy and the galactic dynamo 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 Magnetic buoyancy and the galactic dynamo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic buoyancy and the galactic dynamo will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-807231