Published online by Cambridge University Press: 14 August 2015
To test the validity of the assumption of a ‘current-free’ magnetic field in the atmosphere above sunspots, we measured all three parameters of the magnetic field in an active region and compared it with the calculated current-free field according to the solution proposed by Schmidt. We found important differences between the calculated and the measured field.
We refer to an earlier paper where the objections to the ‘current-free field’ were that the calculated field has too simple a configuration to account for the fine structure observed in Hα and other solar observations.