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Astrophysics Research Centre

School of Mathematics and Physics

Using the Jansky Very Large Array and the 100m Green Bank Telescope to Study Turbulence and Coronal Magnetic Fields

  • Submitted by: Adam Kobelski, National Radio Astronomy Observatory
  • Authors: A.R. Kobelski, T.S. Bastian, E. Jensen, D. Wexler, C. Heiles, S. Betti
  • Session: Monday morning posters.

The solar wind offers an extraordinary laboratory for studying MHD turbulence, turbulent dissipation, and heating. Radio propagation phenomena can be exploited as probes of the solar wind in regions that are generally inaccessible to in situ spacecraft measurements. Here, we have undertaken a study with the VLA to observe point-like sources drawn from the JVAS catalog, and 3 VLA calibrator sources, to trans-illuminate the outer corona/inner solar wind. In doing so, we will exploit angular broadening and refractive scintillation to deduce properties of the solar wind along ~100 lines of sight within 7 solar radii of the Sun and a wide range of position angles, a factor 10 improvement over previous studies. By fitting the complex visibilities using well-known techniques we can deduce or constrain a number of key parameters, including the spectral slope of the turbulence at both small (km to 10s of km) and large (thousands of km) scales, determine the presence and evolution of an inner scale, measure the degree of anisotropy, and constrain the topology of the global coronal magnetic field. The inner scale is of particular interest for constraining current theories of turbulence dissipation and heating.

Additionally, we have taken measurements with the 100m Green Bank Telescope to measure the Faraday rotation of STEREO A's and Martian spacecraft’s radio frequency carriers to investigate the magnetic field and magnetohydrodynamic fluctuations of the solar corona at various radial distances and within different structures (specifically the quiet background and coronal mass ejection crossings). These observations show notable fluctuations in the Faraday rotation of the signal, allowing a unique insight into the dynamics of the corona above 1.7 Solar radii.

public/hinode9/schedule/session-01p/v0060.txt · Last modified: 2015/07/30 00:38 (external edit)

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