
%0 Journal Article
%A Melrose, Don 
%A Kennett, Malcolm 
%T Propagation-induced Circular Polarisation in Synchrotron Sources
%J Publications of the Astronomical Society of Australia
%D 1998/07/01
%V 15
%N 2
%P 211-216
%K 
%R https://doi.org/10.1071/AS98211
%U https://www.publish.csiro.au/paper/AS98211 
%X The small degree of circular polarisation observed in some synchrotron sources has a frequency dependence that is not consistent with simple predictions based on the intrinsic circular polarisation of synchrotron emission. The suggestion is explored that the circular polarisation arises as a propagation effect within the source. The physical basis of this alternative mechanism is the fact that the natural wave modes of a synchrotron emitting gas are linearly polarised, allowing partial conversion of linear into circular polarisation as in a quarter-wave plate. A relativistic rotation measure (RRM) is defined to characterise the magnitude of this effect. 
