The current state of the art concerning measurements of the Zeeman splitting of hydrogen line spectral features is described. An early claim, that a magnetic field of 2.5 x 10-5 Gauss had been deteoted in a cloud in the direction of Taurus A, is shown to be unfounded, The present evidence indicates that only an upper limit to the magnetic field within a cloud can be set. This is of the order of 5 x 10-6 Gauss. ~le experimental methods used, and the difficulties involved, in tryine to measure this Zeeman splitting are discussed in detail. The work done in determining more accurately the parameters of the clouds being searched for magnetic fields is outlined. Measurements of the linear polarization of radio sources at 2lcm are described and the earlier results are shown to have been subject to severe errors as a result of the method of analysis. The results of more accurate measurements are presented and compared with values obtained elsewhere. Rotation measure data, obtained elsewhere, is discussed in relation to the magnetic field existing within the galaxy. All the data mentioned above is finally combined in an attempt to obtain a picture of the magnetic field configuration in the solar neighbourhood.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:605171 |
| Date | January 1965 |
| Creators | Verschuur, Gerrit Laurens |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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