The role of Hall and Pedersen conductivity profiles in the ionospheric response to magnetospheric driving

Solar wind–driven disturbances excite Alfvénic perturbations in the Earth’s magnetosphere that propagate along geomagnetic field lines toward Earth, with the ionosphere being the inner boundary where field-aligned currents close. Horizontal gradients in the Hall and Pedersen conductances have previously been invoked to explain rotations of the convection pattern in response to magnetospheric forcing (Lotko et al., 2014).

We employ a time-dependent 2D model of the ionosphere driven by the magnetosphere. The radial magnetic field perturbations are generated inductively, numerically solving the induction equation  along with the two-fluid equations, allowing us to capture the gradual formation of the convection pattern and to understand the role of the ionization/recombination processes or pressure gradients.

We investigate the temporal evolution of the system under a range of realistic and hypothetical high-latitude Hall and Pedersen conductance distributions. We find that gradients in either Hall or Pedersen conductance can alter the convection pattern, in contrast to earlier results suggesting that only Hall conductance gradients play a role.