Solar flares, concurrent cosmic ray bursts and subsequent geomagnetic storms

Abstract

Five large cosmic ray bursts in connection with solar flares have been observed till now. Two of them were followed by geomagnetic storms associated with cosmic ray disturbances when both the phenomena could be closely correlated. Two of the biggest geomagnetic storms recorded at Alibag have also been considered. Just as in geomagnetism, it was though that a study should be made not merely of individual flares but also of the evolution and progress of solar active regions for the above phenomena. Big cosmic ray bursts along with solar flares occurred when the active regions on the sun had a long previous history of more than usual activity either when the active region was near the C. M. or near the western limb of the sun. In the former case a geomagnetic storm followed which could be closely correlated with a simultaneous cosmic ray disturbance. In the latter, nosuch type of geomagnetic disturbance followed. In the case of the two biggest geomagnetic storms, the active region was more ephemeral in age or history. The large flares occurred at the period of dissolution of the region soon after its C. M. passage. The particles responsible for the very big solar flares have atomic numbers neither too low nor too large in the periodic table and are positively charged. The frequency of such events being small the elements involved must be from those in the sun whose abudence is relatively scarce. Detailed spectroscopic examination would decide what these elements are (Sr, Ba. etc.).