ANTARCTIC RESEARCH AND DATA ANALYSIS. A PROTON-COLLISION MECHANISM FOR THE PRODUCTION OF SPREAD F IRREGULARITIES.
Scientific rept. no. 16,
AVCO CORP WILMINGTON MASS RESEARCH AND ADVANCED DEVELOPMENT DIV
Pagination or Media Count:
It is well known that the spread echoes observed on Arctic and Antarctic ionograms arise from reflections or scattering from irregularities in the F region. The paper attempts to explain the formation mechanism for such irregularities. The assumption is made that field-aligned irregularities are caused by low energy or 20 kev charged particles spiralling along magnetic field lines and penetrating to F-region heights. Ionization is created along the field lines by collisions, and it remains fieldaligned due to the effects of diffusion. It is suggested that this mechanism is operative at all times but with some variation in intensity. During daytime the irregularities produced in this manner are usually masked by higher electron densities given by photoionization. Supporting evidence for the proposed production mechanism is given by the diurnal, seasonal, and geographical variations in spread-F occurrence, and its correlation with magnetic activity. Author