Expert: Jayendra Upadhye - 4/19/2004

Question
What does the color of the prominenses tell us about them? What does there shape tell us?

Answer
Hi Koby,
I would say that was a good question. (because it has potential to make one go into spectroscopy, emission spectra, doppler related study and MHD or Magneto Hydro Dynamics and so on..)
Solar prominences are cooler and denser plasma structures
embedded in the hot and tenuous solar corona.
velocities vary from 10s of km/sec to 100s of kn/sec.
Radiative heating of this gas is due to illumination from the photospheric light (as emitted at approx. 6000 degrees centigrade by the solar surface and coronospheric light at temperatures many many times higher.
Well as in the case of all "color" related studies in astronomy..firstly it tells us about its constituent gas and its temperature.
Mostly that is the spectrum of light as emitted by hot hydrogen.
Its study reveals internal motions within the body of the prominence too (doppler shifting).
Regarding shape..well all plasma is ionised matter and thus
subject to influence of a magnetic field. (the right hand palm rule).
Depending on inital velocities the shape describes complete  loops/whorls or a horseshoe shape.
All the foregoing was to best of my knowledge..
As I always say, please do look up the www for more info if you can spare time.(It is the ultimate expert!)
MHD you will find interesting too as it is considered as good source of alternative power if and when tamed.
Jayen.