| Description: | Turbulence in the diffuse ISM produces random variations in the gas density and magnetic field. However, extracting physically useful information from observations, that can then be compared to theoretical ideas and the results of numerical simulations, is not straightforward. I will discuss recent work on: (i) the observed distribution of average gas densities along different lines-of-sight; (ii) how random variations in Faraday rotation can be interpreted and (iii) what fluctuations in synchrotron intensity can tell us about the distribution of cosmic rays.
Above: The relative intensity of fluctuations to the local mean in the Milky Way radio emission at 408 MHz (408 MHz data from Haslam et al. 1982). The colour scale runs from 0.1 (weak fluctuations) at high latitudes to 8 (strong fluctuations) in the disc: the intensity of the fluctuations is related to the relative distributions of magnetic fields and cosmic rays. |
