Estimation of Magnetospheric Plasma Parameters from Whistlers Observed at Low Latitudes

Whistler observations during night-time made at low-latitude Indian ground stations, Jammu (geomag. lat. 29°26'N; L = 1.17), Nainital (geomag. lat. 19°1'N; L = 1.16) and Varanasi (geomag. lat. 14°55'N; L = 1.11) are used to deduce electron temperature and electric field in the vicinity of the magnetospheric equator. The accurate curve-fitting and parameter estimation techniques are used to compute nose frequency and equatorial electron density from the dispersion measurements of short whistlers recorded at Jammu, Nainital and Varanasi. In this communication we estimate the magnetospheric electron temperature and electric field from the dispersion analysis of short whistlers observed at low latitudes using different methods; the results obtained are in good agreement with those reported by other workers. The upper atmosphere environment is impacted by energetic particles, solar radiation and interplanetary magnetic fields that drive 'space weather' disturbances in the region, leading to strong electric currents, order of magnitude changes in neutral density and temperature, and major redistribution of plasma. At the same time, circulation and variability of the upper atmosphere are dramatically impacted by waves carrying energy and momentum upward from hurricanes, thermal tides and surface features. This region is where space and Earth's atmosphere interact, forming a critical boundary that must be studied to advance our understanding of the whole Earth system.