9320575 Mikic The investigators will study the physical properties of active-regions in the sun's corona from the topology of the magnetic field. In a prior grant, the investigators developed a technique to determine the coronal magnetic field configuration from vector magnetograph measurements of the photospheric magnetic field. Vector magnetographs measure the Zeeman splitting of magnetically sensitive spectral lines. The investigators will study a numer of different properties of coronal magnetic fields. They will compare the topology of active-region coronal fields to observational features believed to trace field lines. They will also relate the morphology of flare phenomena to the structure of the coronal magnetic fields. They will study the evolution of the coronal field above an active region using a sequence of magnetograms and develop realistic models of active region magnetic fields. ***
