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		| Paper: | 
		Magnetic-Field Fluctuations Around the Radio Galaxy 3C 31 | 
	 
	
		| Volume: | 
		386, Extragalactic Jets: Theory and Observation from Radio to Gamma Ray | 
	 
	
		| Page: | 
		104 | 
	 
	
		| Authors: | 
		Laing, R.A.; Bridle, A.H. | 
	 
	
	
		| Abstract: | 
		We present an analysis of the magnetic-field fluctuations in the magnetoionic medium in front of the radio galaxy 3C 31 derived from rotation-measure (RM) fits to high-resolution polarization images. We first show that the Faraday rotation must be due primarily to a foreground medium. We determine the RM structure functions for different parts of the source and infer that the simplest form for the power spectrum is a power law with a high-frequency cutoff. We also present three-dimensional simulations of RM produced by a tangled magnetic field in the hot plasma surrounding 3C 31, and show that the observed RM distribution is consistent with a spherical plasma distribution in which the radio source has produced a cavity. | 
	 
	
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