Sudden frequency deviations, solar extreme ultraviolet bursts, and solar radio bursts

An investigation has been made of the interrelationship of solar extreme ultraviolet (EUV) bursts, solar radio bursts, and terrestrial ionospheric sudden frequency deviations (SFD's). No direct general relationships between radio spectra or burst intensities and SFD incidence or magnitude (Delta f) have been found. If the EUV enhancement is greater than 3 percent at Lambda 304 or Lambda 630 A, there is an 85 percent probability of occurrence of an SFD. Time of maxima of EUV and radio bursts are found to coincide extremely well. (Author).