Abstract
We observe coronal mass ejections using coronagraphs that block out the photosphere to reveal the faint corona. They detect the light that has been Thomson scattered off the free electrons in the CME plasma. Consequently we may obtain information about the CME using our knowledge of Thomson scattering physics. This chapter reviews the theory of Thomson scattering, how CMEs are observed with coronagraphs and heliospheric imagers, and how we may extract information about them.
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Notes
- 1.
Note that all of these early works pre-date the discovery of the CME.
- 2.
This is the same χ defined earlier as the scattering angle.
- 3.
This can be either q t or q n , it doesn’t matter as the equation is the same.
- 4.
This is not the same z as in Fig. 4.3 and the one we used in the coordinate deconstruction.
- 5.
Both density and incident intensity fall off with an approximate 1 ∕ R 2 factor as we move away from the Sun.
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Howard, T. (2011). How We Observe CMEs. In: Coronal Mass Ejections. Astrophysics and Space Science Library, vol 376. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-8789-1_4
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DOI: https://doi.org/10.1007/978-1-4419-8789-1_4
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