Solar coronal magnetic field mapper

Abstract

The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. The Hanle effect in UV spectral lines is a largely unexplored diagnostic of coronal magnetic fields with a very high potential. Here we study the magnitude of the signal to be expected for typical coronal fields for the particular example of the hydrogen Lyman a line and show that this line may be useful for such measurements, in particular in combination with a disk imager. We propose that an EUV coronal magnetic field mapper should be a central part of the science payload of any future spacebased solar observatory.