Magnetic fields and flare activity

The structure of the magnetic fields and vertical electric currents are compared with flare activity in the active region Mc Math 9740 during the centre-meridian passage 28.10.1968. The distributions of vertical electric current density are calculated on the basis of transversal component of the observed photospheric magnetic field. The distribution of transversal magnetic field measured in the Fe I λ 5250 A line has been compared with the structure of the potential field calculated from the observed vertical component. It is found that practically all bright knots of flares appear in the area of strong electric currents which are located closely to the neutral line of the longitudinal magnetic field