Flare-induced changes of the photospheric magnetic field in a $\delta$-spot deduced from ground-based observations

Peter Gömöry, Horst Balthasar, Christoph Kuckein +6

Aims: Changes of the magnetic field and the line-of-sight velocities in the photosphere are being reported for an M-class flare that originated at a $\delta$-spot belonging to active re…