Temporal and spatial variation of physical parameters in a quiescent prominence.
Abstract
The emission lines He 3889 A, H_8_ and Ca^+^IR_3_ are observed simultaneously in a prominence over a total of 4 hours. The time variations of the He 3889 / H_8_ emission ratio R, the thermal and the non-thermal line broadenings T_kin_ and ξ, respectively, are compared with those of the Doppler shift, v_D_, for 10 spatial locations along the slit. The time-averaged spatial variations along the slit show an increase of R, T_kin_, and ξ with height related to a decrease of the H_8_ emission, E_tot_(H_8_), in agreement with other authors. The short-time fluctuations show that quasi-oscillations, known from Doppler shifts, also exist for other physical parameters. The long-term variations over the total of 4 hours indicate a smooth increase of R, T_kin_, and ξ at the upper parts of the prominence, resembling the known spatial behaviour of these parameters at prominence edges. Also the well known anti-correlation of the emission ratio R and the E_tot_(H_8_) occurs in the long-term behaviour. We suggest that the decrease of E_tot_(H_8_) parallel with the increase of R might be related to a dissolution of the prominence yielding a smaller density of fine-structures.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1994
- Bibcode:
- 1994A&A...286..639B
- Keywords:
-
- Calcium;
- Emission Spectra;
- Helium;
- Hydrogen;
- Iridium;
- Line Spectra;
- Solar Oscillations;
- Solar Prominences;
- Spatial Distribution;
- Temporal Distribution;
- Chromosphere;
- Power Spectra;
- Radial Velocity;
- Solar Atmosphere;
- Solar Physics;
- SUN: PROMINENCES;
- OSCILLATIONS;
- TECHNIQUES: RADIAL VELOCITIES