Faraday rotation and the turbulent structure of the Galaxy |
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Authors: | J C Carvalho D Ter Haar |
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Institution: | (1) Dept. of Theoretical Physics, Oxford, England |
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Abstract: | We extend Jokipii and Lerche's analysis of the turbulent structure of our Galaxy by means of a study of the rotation measure of extragalactic sources. Like them we use a simple, statistically homogeneous and isotropic disc model of the Galaxy and assume that the magnetic field has both an average component and a fluctuating one. We assume that the electron density is proportional to some power of the magnetic field (N
eB
n with 1n2). Using the rotation measure data on 242 extragalactic sources given by Vallée and Kronberg we consider both an exponential and a Gaussian two-point correlation function for the (Gaussian) fluctuating component of the magnetic field with a correlation lengthL. We find reasonable agreement between theory and observations for an average magnetic field of about 3 G, a fluctuating magnetic field component with an amplitude of about 2.6G, an average electron density of about 0.03 cm–3, a fluctuating density component of about 0.05 cm–3, and a correlation length of about 300 pc. |
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