Author: United States. Environmental Data Service
Publisher:
Published: 1976
Total Pages: 138
ISBN-13:
DOWNLOAD EBOOK →Author: World Data Center A for Solar-Terrestrial Physics
Publisher:
Published: 1968
Total Pages: 92
ISBN-13:
DOWNLOAD EBOOK →Author: Hermine Vloemans
Publisher: Springer Science & Business Media
Published: 2012-12-06
Total Pages: 308
ISBN-13: 9401022313
DOWNLOAD EBOOK →Sudden Ionospheric Disturbances resulting from an interaction of the Solar Flare radiation with the constituents of the upper atmosphere constitute one of the three major aspects of ground level monitoring of solar flares -the other two being optical observations of flares, and the observations of solar bursts in radio wavelengths. SIDs, therefore, form a major part of flare monitoring programme in many observatories. Unlike the other two, however, the ionospheric effects of flares provide one major additional source of interest - the reaction of the ionospheric plasma to an impulsive ionization. The high atmosphere provides a low pressure laboratory without walls in which a host of reactions occur between electrons, ions and neutral particles. The resulting products and their distributions may bear no resemblance to those of the primary neutral constituents or their direct ionization products. The variations with the time of the day, with season and with solar activity that form the bulk of the ionospheric measurements are too slow to allow any insight into the nature of these ionospheric reactions whose lifetimes are often very short. The relaxation time of the ionospheric ionization is only a few minutes or fraction of a minute in the lower ionosphere and in the E-region and is about 30 min to an hour at 300 km. The flares provide a sudden short impulse comparable to these time scales.