On the relation between magnetic field strength and Wilson depression in sunspots

Abstract

At the Solar Tower Telescope of Kodaikanal Observatory, we obtained Zeeman spectra of sunspots on their disk passage during 1979-84 (Solar max. 21). Using this data and full disk white light pictures obtained at the observatory, we are examining the possible relation between Wilson Effect(WE) and longitudianal magnetic field strength (Bl)of selected spots. Preliminary results indicate that WE does not depend upon B1. Further, a large number of spots do not exhibit WE. It appears that the magnetic field configuration, rather than field strength, plays the key role in the occurrence or absence of WE.