1. Radio Remote Sensing of the Solar Corona
Steven R. Spangler… Department of Physics and Astronomy, University of Iowa

2. What we would like to know about the corona
Vector magnetic field
Plasma density
Temperature
Characteristics of turbulence

3. We are helped by direct spacecraft measurements in interplanetary space

4. How do we measure B in the corona itself?
Direct measurements out here
Zeeman measurements here

5. Radioastronomical propagation measurements
Technique discussed here: Faraday rotation

7. Measuring Properties of Turbulence: Interferometer Phase Scintillations

8. The Instrument: The Very Large Array Radiotelescope
Operated by the National Radio Astronomy Observatory (NRAO)

9. The Very Large Array

10. The North Liberty (Iowa) Radio Telescope

11. Extragalactic sources provide “constellations” of background objects
Mancuso & Spangler, Astrophys. J. 539, 480, 2000

12. VLBI Phase Scintillations: the technique

13. Phase Scintillations of a VLBI Interferometer: the data

14. Agreement of model and observed rotation measures

15. Conclusions and Summary
Radio remote sensing observations can measure properties of the plasma in the solar corona.
These observations have provided information on the strength and structure of the coronal magnetic field and the properties of turbulence.
Future investigations (observations being analysed, or in planning) can improve on the above results