Ionospheric conductivity height profile and conductance spatial distribution changes due to Earth magnetic field variations

ELIAS, ANA G.; BRUNO S. ZOSSI; FAGRE, MARIANO

Hefei

Workshop; 10th Workshop on Long-term Changes and Trends in the Atmosphere; 2018

University of Science and Technology of China

The ionospheric conductivity is extremely important in geophysical processes and plays a critical role in magnetosphere-ionosphere-thermosphere coupling processes. The upper atmosphere electrodynamics depends on many parameters, including the Earth?s magnetic field, which varies greatly with time. The present field can be approximated by a magnetic dipole that accounts for ~80% of the magnetic field of the Earth?s surface, plus multipolar components making up the remaining ~20%. During a polarity transition the field magnitude diminishes to about 10% of its actual value at expense, most likely, of decreasing the dipolar component and becoming mostly multipolar in nature. The effects of geomagnetic field variations on height profile of Hall and Pedersen conductivities and dominant conducting ions are analyzed in the present work, extrapolating the magnetic field to a possible reversal scenario. Significant changes are observed in these profiles with noticeable increasing peak heights under certain conditions. During the actual magnetic field configuration, conductivities? peak height occurs within 100-150 km range, the main conducting ion is NO+. For a decreased field configuration, conductivities maximize at higher levels, reaching 200 km and higher, where ~80% of the ions are O+. Hall and Pedersen conductances? spatial structure is also analyzed. Both conductances change significantly with sharp spatial gradients as a consequence of an overall hyperbolic dependence of conductances with magnetic field.