Small Cosmic Ray Variations Produced by Solar Flares

The small effects produced by solar flares on cosmic ray intensity has been investigated.In the first part of the analysis, flares of importance 2+ or greater were selected.Cosmic ray data from the neutron monitor in Lincoln and Deep River were grouped ranging in time from 3 hours before the flare onset to 8 hours after it.The superposed epoch method was used with the following results: (a) no effect other than daily variation was found when different periods of time were selected for the analysis, (b) no effect was found when the flares were classified according to the solar regions where they occurred.Lincoln showed some tendency to increase after zero hour when flares which occurred on the western part of the sun were taken, but this was not found in Deep River. In the second part of the analysis, only those flares accompanied by a type IV radio emission were taken, irrespective of their importance.The effect found was of the order of 1% for Lincoln and Deep River, appearing after the zero hour, lasting for 3 to 4 hours. The contradictory results obtained by many authors is a hint that not all of the factors contributing to these effects are being taken into account. Advisor: R. L. Chasso