The stability of stratified, rotating systems and the generation of vorticity in the Sun
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 426:2 (2012) 1546-1557
On linear dust–gas streaming instabilities in protoplanetary discs
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 415:4 (2011) 3591-3598
FLUID DYNAMICS A turbulent matter
NATURE 470:7335 (2011) 475-476
When is Uniform Rotation an Energy Minimum?
Mexican Journal of Physics E (2010)
Abstract:
A simple variational calculation is presented showing that a uniformly rotating barotropic fluid in an external potential attains a true energy minimum if and only if the rotation profile is everywhere subsonic. If regions of supersonic rotation are present, fluid variations exist that could take the sytem to states of lower energy. In any given system, these states may or may not be dynamically accessible, but their existence is important. It means that extending the degrees of freedom available to the fluid (say by weak magnetic fields) may open a path to fluid instabilities. Whether astrophysical gaseous nebula tend toward states of uniform rotation or toward more Keplerian core-disk systems appears to be largely a matter of whether the rotation profile is transonic or not. The suggestion is made that the length scale associated with coherent molecular cloud cores is related to the requirement that the cores be stable and rotate subsonically.Radiative and dynamic stability of a dilute plasma
Astrophysical Journal Letters 720:1 PART 2 (2010)