Early Detection of a Solar Flare

Book excerpt: Solar X-ray, extreme ultraviolet, H[alpha] and radio emission were studies to determine what solar radiation is best suited for an automatic flare alarm system aboard a satellite for the detection of the start of a solar flare. Although hard X-rays ([lambda] “1 Å), centimeter-wavelength solar radio bursts, and flashes at certain EUV wavelengths usually have faster rise times and peak earlier than soft X-rays in the 2-16 Å range, the data available to date show that on the average the start time of the 2-16 Å X-rays occurs earlier than the start times for these other types of data. The early start times and large percentage increase of 2-16 Å X-rays make this radiation the best suited for the automatic detection of solar flares for the present state of the art of solar radiation measurements.