Are Astrophysical Shear Flows Able to Heat Themselves?
Author: Rogava, Andria
Source: Astrophysics and Space Science, Volume 293, Numbers 1-2, September 2004 , pp. 189-196(8)
Abstract:The mechanism of the shear-induced nonmodal self-heating of flows is described. This phenomenon comprises three essential steps: (i) waves and/or vortices get excitedwithin a flow; (ii) they amplify nonmodally, due to the presence of the shear flow, extracting a part of the flow kinetic energy; (iii) high amplitude waves and/or transiently amplified vortices undergo viscous decay and/or magnetic diffusion and give, in the form of the heat, a part of their excessive energy back to the flow. I argue that this phenomenon may play a formidable role in the dynamics of different, especially kinematically complex, astrophysical shear flows (ASF), viz: swirling macrospicules in the Solar atmosphere (solar tornados), galactic (stellar) and extragalactic jets.
Document Type: Research Article
Affiliations: Dipartimento di Fisica Generale, Universitá degli Studi di Torino, Italy,
Publication date: 2004-09-01