Astron. Astrophys. 358, 741-748 (2000)

4. Conclusions

In this paper we discuss the quiet Sun in terms of three intensity distributions; the internetwork, the `normal' network and the bright network. From an analysis of emission measures we find that the slopes between temperatures of 5.4 log T_e 6.0 are different in each of the three intensity regions. The change in the slope with intensity suggests that there are different density structures present in each region. An analysis of the area of emission in each distribution suggests that in the combined network region (normal network and bright network) there are two populations of network structures, a low transition region group and a coronal group.

Using magnetograms, we have found that the bright network is composed of coronal funnels and network loops. Futhermore these loops and funnels are continuous structures reaching coronal temperatures, as their expansion can be seen all the way from OIII up to FeXVI . For log T_e 5.7, up to 30% of the total radiative losses are attributed to the bright network emission, and thus by continuous layers in a stratified atmosphere. The structure of the combined network is seen to change substantially above a temperature of approximately log T_e=5.7.

Cross-sectional areas estimated from redshift values suggest that what is seen in bright network regions is the result of flux tube expansion in loops and funnels into the corona, accompanied by a downflow or possibly upflow of material.

Future work in this area would involve time series of rasters to examine the variation of network structures with time. These rasters combined with simultaneous magnetogram observations could help to further identify the `Dowdy' component in the network by allowing a more comprehensive statistical analysis to be carried out.

© European Southern Observatory (ESO) 2000

Online publication: June 8, 2000
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