The Effects of Magnetic Storm Phases on F-Layer Irregularities from Auroral to Equatorial Latitudes

Abstract

Abstract : The aim of the research is to identify the necessary and sufficient conditions for the creation of ionospheric irregularities, primarily at equatorial latitudes. We are searching for means of identifying the parameters at high latitudes which produce effects at equatorial latitudes. The instability processes by which F layer irregularities develop are different for high latitude and for equatorial irregularities. At high latitudes, electric field changes during a storm, which can be highly localized, produce high intensity irregularities. At equatorial latitudes instability mechanisms, primarily the Rayleigh Taylor instability, has been thought to be the primary reason for the growth of plume like irregularities near the magnetic equator. Using radio and optical observations, we would like to find the triggering mechanism for equatorial irregularity development. Deep fades occur on the 250 MHz transmissions from FLEETSATCOM and AFSATCOM at equatorial, auroral, and polar latitudes. There is also phase and amplitude scintillation on the 1.2 and 1.6 GHz higher frequencies of the Global Positioning System's set of 24 satellites. In the IRIDIUM system at 1.6 GHz, the U.S. government has reserved several channels. Simply put, if we knew the forcing functions we could have the opportunity to forecast and predict when these irregularities interfere with communication and navigation systems. During a magnetic storm, the electric field increases at auroral latitudes. The turbulence resulting produces auroral and ionospheric irregularities. Slowly a shield is built up at high latitudes. At times the shield prevents activity at high latitudes from penetrating to equatorial latitudes. At other times, only a weak shield develops that prevents or enhances the lifting of the F layer at equatorial latitudes.