K-Line emission and the integrated surface magnetic field on the sun

Abstract

We have made plots of the Ca II K line emission vs the global surface magnetic field for the sun for the years 1975–1982 representing both solar minimum as well as solar maximum epochs. These plots show that the K-line emission is not related to the global magnetic fields. An explanation for the absence of a correlation is offered. A direct measurement of the global magnetic field of the sun or similar stars will give an algebraic sum of the magnetic fields present on the surface, whereas the K-line emission will be additive Irrespective of the polarity of the fields. K-line emission being a sign insensitive indicator of magnetic field, is advantageous and with a proper calibration, the surface fields and the partition of fields according to signs can be evaluated through a calibration. This possibility is extended to sun-like stars where the presence of surface fields can be established reliably.