Evidence for the two fluid scenario in solar prominences

Abstract

This paper presents observational evidence of the different dynamical behavior of neutral and ionized species in solar prominences. The analysis of a time-series of Sr II 4078 A and Na D spectra in a quiescent prominence yields systematically larger Doppler shifts (line-of-sight velocities) for the ions V_LOS(Sr II)= 1.22 x V_LOS (Na D). Both lines show a 30 min oscillation of good coherence. Sixteen hours later the same prominence underwent marked morphological changes (with a rising dome), and the Sr II velocity excess drops to V_LOS(Sr II)=1.11 x V_LOS(Na D). The same excess is found for the line pair Fe II 5018 A and He I 5015 A. The widths of the ionic lines, mainly non-thermally broadened, are not related to the macro velocities. The emission ratio of Na D and Sr II, a measure of the electron density, yields n_e = 4 x 10^10 1/cm, shows no relation with the V_LOS variation or with height above the limb, and seems to be reduced 16 hr later during the active phase. We apply a new wavelength reference from aureola spectra, which is independent of photospheric velocity fields.

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Cited by in corpus (11)

• The European Solar Telescope
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• Velocity difference of ions and neutrals in solar prominences
• Two-fluid implementation in MPI-AMRVAC, with applications in the solar chromosphere
• Large ion-neutral drift velocities and plasma heating in partially ionized coronal rain blobs
• Shocks and instabilities in the partially ionised solar atmosphere
• Mixing, heating and ion-neutral decoupling induced by Rayleigh-Taylor instability in prominence-corona transition regions
• Future Prospects for Partially Ionised Solar Plasmas: the Prominence Case
• Ionization memory of plasma emiters in a solar prominence
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• MHD waves in the partially ionized plasma: from single to multi-fluid approach