The solar wind provides a unique natural "laboratory" in which plasma turbulence may be investigated in-situ. Turbulence is statistically reproducible. Thus, in this thesis we investigate plasma turbulence in the solar wind through the statistical study of magnetic field observations. In particular, we investigate single-satellite time-series of the magnetic field. We discuss hydrodynamic turbulence, and make parallels between hydrodynamic and magnetohydrodynamic turbulence. In hydrodynamic turbulence a unique scaling relation may be determined from dimensional analysis. Importantly, one may not derive a unique scaling relation for magnetohydrodynamic turbulence from dimensional analysis. Therefore, comparison of observations and turbulence models are key to determining the underlying physics for specific plasma parameters. The inertial range is a range of scales over which energy cascades from large to small temporal-spatial scales. This thesis will predominantly be focused on the anisotropy and scaling of the inertial range within the solar wind. We investigate how sampling a solenoid field, i.e. . B = 0, with a single satellite produces an apparent nonaxisymmetry with respect to the background magnetic field. We also investigate how time-series discontinuities produced by non-turbulent structures alter the statistical analysis of various anisotropy measures. We will find that the commonly held picture of the solar wind, that specific temporal-spatial scales have a distinct physical origin, is an over simplified model. We will show that non-turbulent structures must be removed from the observations in order to analysis the statistics of the turbulence accurately. The work in this thesis helps to constrain theories of plasma turbulence where there is a background magnetic field with a greater magnitude than the root-mean-square magnitude of the turbulent fluctuations.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:582476 |
| Date | January 2013 |
| Creators | Turner, Andrew J. |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/57960/ |
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