indico  First event Previous event Astronomy and astrophysics Next event Last event   | view:  |  manage export to personal scheduler  | 
user login 


Towards Understanding Diffusive Shock Acceleration
  Astronomy and astrophysics

Friday 05 September 2014
from 10:30 to 11:30
at FA31
Speaker : Andrey Beresnyak (Los Alamos National Lab)
Abstract : Acceleration of cosmic rays (CRs) in supernova remnants (SNR) is probably the best known case of shock acceleration. Observations strongly suggest that SNR produce CRs with energies up to 10^15 eV or higher. Thin X-ray rims observed in remnants and short timescale variability points to magnetic field amplification near the shock. In fact, simple estimates show that without field amplification in front of the shock CR production will be negligible. At the same time, the only agent acting in front of the shock are CR themselves. Three approaches has been explored as possible sources of CR-generated turbulence in front of the shock: streaming instability, Bell's instability and the baroclinic term from cosmic ray pressure. While models are being developed, new observations of very short timescale variability appear to strain these models close to breaking point. I will point to several ways to explain rapid variability.

AlbaNova  | Last modified 05 December 2017 10:13  |  HELP