New data on the magnetic structure of quiescent prominences
Résumé
Hanle-effect vector-magnetic-field measurements in the unresolved 5876-A D3 line of He and simultaneous H-alpha or H-beta polarization measurements obtained with the coronagraph polarimeter at Observatoire du Pic du Midi during 1974-1982 are reported for 256 solar prominences of medium and low latitude. The data are presented in graphs, tables, diagrams, and photographs and analyzed statistically to resolve the twofold ambiguity inherent in magnetic/polarimetric measurements of this type. Prominences with maximum heights lower than 30,000 km are found to have field-vector angles (alpha) about 20 deg and fields of about 20 G; those above 30,000 km have alpha 25 deg and fields 5-10 G; the structures correspond to the models proposed by Kippenhahn and Schlueter (1957) and by Kuperus and Raadu (1974), respectively.