Investigation of ESF Triggers using Balloon-Based and Ground-Based Diagnostics

摘要

It is widely believed that gravity waves trigger the occurrence of F- region irregularities. This inference of gravity wave seeding the irregularities was based on the Range-Time-Intensity maps of the incoherent scatter radar echoes. The radar-returned echoes of F-region irregularities are in the form of waves, with periodicities ranging from 60 minutes to 120 minutes. But, till this date no measurements have been carried out before the irregularities are actually triggered to conclusively answer this question of gravity waves as the seeds for ESF onset. As a part of this work, two BU-built optical spectrographs will be flown on board a high-altitude balloon from the National Balloon Launch facility in Hyderabad, India to obtain the wave characteristics before the occurrence of the F-region irregularities. These spectrographs will make measurements of airglow emissions at three wavelengths (280.0nm, 557.7nm and 630.0nm) that originate at different altitudes; namely 85, 100 and 230 km, respectively. The measurements will be carried out in different orientations such that the combined data can be used to obtain two-dimensional daytime maps of these emissions. Such maps will be processed to obtain information on the spatial and temporal characteristics of the wave features. In addition, data from this experiment will be well complemented by both optical and radio diagnostics operating from the ground at various locations in India.