Geomagnetic crochets associated with proton flares.

The effect of solar flares on geomagnetic variation, designated by sfe (also known as crochet), has been investigated by several workers using observations over a range of altitudes. The present paper analyzes magnetogram data collected over a period of 13 years for crochets associated with proton flares. A total of 15 sfe's associated with proton flares became available for study. A total of 92 sfe's associated with normal flares are also studied for comparison purposes. The characteristics describing a crochet are the rise time, decay time, total duration, amplitude, and the nature of decay. It is shown that the sfe's associated with proton flares exhibit longer rise time and total duration than those of normal flares and that the proton flares which produced sfe's have east-west asymmetry as regards their position on the solar disk. In addition, the region of enhanced conductivity is in the D region below the normal electrojet.