Journal des sciences de la Terre et du changement climatique

Abstrait

Solar Wind-Magnetosphere-Ionosphere Coupling on Polar Cusp

RK Mishra, SC Dubey

The Earth’s magnetosphere and upper atmosphere can be greatly perturbed by variations in the solar luminosity caused by disturbances on the Sun. The polar cusp ionosphere important part of near- earth space which best monitored by ground based observation made in the remote polar regions, Antratica seems certain to play a key role in the future exploration. The polar region is characterized by direct entry of solar wind particles along magnetic field line projecting to the dayside magnetopause (outer boundary of the magnetosphere). Thus polar cusp ionosphere provides splendid window for examining processes transferring solar wind mass and momentum to the magnetosphere. The state of near-Earth space environment is governed by the Sun and is very dynamic on all spatial and temporal scale. The geomagnetic field which protects the Earth from solar wind and cosmic rays is also essential to the evolution of life; its variations can have either direct or indirect effect on human physiology and health state even if the magnitude of the disturbance is small. Geomagnetic storms are seen at the surface of the Earth as perturbations in the components of the geomagnetic field, caused by electric currents flowing in the magnetosphere and upper atmosphere. Ionospheric and thermospheric storms also result from the redistribution of particles and fields. Global thermospheric storm winds and composition changes are driven by energy injection at high latitudes. Storm effects may penetrate downwards to the lower thermosphere and may even perturb the mesosphere. Many of the ionospheric changes at mid-latitude can be understood as a response to thermospheric perturbations. The transient bursts of solar energetic particles, often associated with very large solar flares, have been observed to have effects on the Earth’s middle and lower atmosphere, including the large-scale destruction of polar stratospheric and tropospheric ozone. In the present, we have discussed effect of solar influences on earth’s magnetosphere and upper atmosphere that are useful to space weather and global warming.