Abstracts > Abstract list by author > Oliver Ramon

Partially ionized plasma downflows and vertical threads in solar prominences
Ramon Oliver  1, *@  , Roberto Soler  1@  , Teimuraz Zaqarashvili  2@  , Jaume Terradas  1@  , Maxim Khodachenko  2@  
1 : Universitat Illes Balears  (UIB)
Departament de Física. Edifici Mateu Orfila. C. Valldemossa, km 7,5. E-07122 Palma de Mallorca -  Spain
2 : Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Space Research Institute Austrian Academy of Sciences Schmiedlstr. 6 A-8042 Graz -  Austria
* : Corresponding author

Observations of limb prominences often show material falling along vertical threads and moving with an acceleration smaller than that of free-fall. A simple partially ionized plasma model is used to investigate these vertical downflows, which are generated by a mass condensation in the corona. From our calculations, the mass injection gives rise to the formation in ~200 s of a dense blob that falls with a roughly constant acceleration of 15–70 m s$^{−2}$ and a density of 4–10 × 10$^{-11}$ kg m$^{−3}$.

For a fully ionized plasma it is found that the gas pressure gradient is responsible for reducing the effect of solar gravity. In the absence of charged particles, neutrals behave like a fully ionized gas. In a partially ionized gas the mass condensation gives rise to the formation of a neutral and a charged blob that, in the absence of friction between these two species, fall with different accelerations. The friction force, however, plays a prominent role since it quickly couples charged particles and neutrals and makes them fall jointly with a constant acceleration.

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