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Plasma parameters in quiescent prominences

Authors: Eberhart Jensen; Jun Elin Wiik;

Plasma parameters in quiescent prominences

Abstract

From a set of four basic parameters; temperature, T(T e = Ti), mass density, p, degree of ionization, x, and magnetic field strength, B, parameters are derived that characterize the properties of the plasma in quiescent prominences. Transport coefficients are of particular interest as the prominence plasma is far from homogeneous. Connected with the fine structure steep gradients must exist both in temperature, density and in the magnetic field strength. As the time constants in the fine structure are of the order of minutes the coupling to the magnetic field will lead to induced currents and ohmic losses. With a moderate filling factor of the plasma threads, the prominence plasma will be "porous" to radiation. This property, which changes with time and must be very different in different parts of a prominence, will influence the degree of ionization, which is the most poorly known parameter in our set. Specification of the damping lengths for Alfv~n-waves, fast mode and acoustic waves at the end of our table requires knowledge of a fifth parameter, the period of the waves, denoted by ~. The "background" medium that surrounds the cool prominence fine structure elements must have corona-like properties probably modified in varying degree by the presence of prominence matter. This second constituent has been ignored in the following. Our basic parameters are known from observations with considerable difference in accuracy. We have used the intervals indicated in "The Hvar Reference Atmosphere of a Quiescent Prominence" (These proceedings) as our source. We thus obtain two values of the parameters in our table, representing an upper and a lower limit. For some parameters the resulting interval comes out to be rather liberal, reflecting considerable uncertainty in our knowledge. For others, such as gas

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
5
Average
Top 10%
Top 10%
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