Title: Radio Remote Sensing of the Solar Corona
1Radio Remote Sensing of the Solar Corona
Steven R. Spangler Department of Physics and
Astronomy, University of Iowa
2What we would like to know about the corona
- Vector magnetic field
- Plasma density
- Temperature
- Characteristics of turbulence
3We are helped by direct spacecraft measurements
in interplanetary space
4How do we measure B in the corona itself?
Direct measurements out here
Zeeman measurements here
5Radioastronomical propagation measurements
Technique discussed here Faraday rotation
6(No Transcript)
7Measuring Properties of Turbulence
Interferometer Phase Scintillations
8The Instrument The Very Large Array
Radiotelescope
Operated by the National Radio Astronomy
Observatory (NRAO)
9The Very Large Array
10The North Liberty (Iowa) Radio Telescope
11Extragalactic sources provide constellations of
background objects
Mancuso Spangler, Astrophys. J. 539, 480, 2000
12VLBI Phase Scintillations the technique
13 Phase Scintillations of a VLBI Interferometer
the data
14Agreement of model and observed rotation measures
15Conclusions 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