Abstract


  VISCOSITY IN THE TURBULENT, COLLISIONLESS SOLAR WIND

  P. Subramanian, Indian Institute of Science Education and Research, Pune (IISER Pune), p.subramanian@iiserpune.ac.in

Several astrophysical situations, ranging from hot accretion disks around black holes to the solar
wind, are known to involve turbulent collisionless plasmas. Transport coefficients such as viscosity
and conductivity in such situations cannot be calculated using traditional methods that are suited only
to collisional plasmas. We have recently demonstrated the use of a rather simple kinetic prescription
for turbulent viscosity that seems to yield very encouraging initial results for the deceleration of fast
coronal mass ejections from the Sun under the influence of viscous drag against the ambient solar
wind. Given the success of this prescription, we propose to understand it better and cast it in the
language of long-standing formalisms such as the k-epsilon turbulent viscosity (traditionally used in
fluid mechanics) and the double-adiabatic closure scheme (traditionally used in plasma physics).