Magnetotail asymmetry from ionospheric Hall conduction

Satellite measurements show that the distributions of high-speed plasma flows at distances of 10 to 30 Earth radii in Earth’s magnetotail neutral sheet are highly skewed toward the premidnight sector. The flows are a product of the magnetic reconnection process that converts magnetic energy stored in the magnetotail into plasma kinetic and thermal energy. Global numerical simulations are being used to investigate the role of the electrodynamic interaction between Earth’s magnetosphere and ionosphere, in particular, the meridional gradient in the ionospheric Hall conductance, in producing observed asymmetries. The simulation experiments are designed to address the following questions:

  1. What controls the relative diversion of Hall current into field-aligned and secondary ionospheric currents at Hall conductance gradients?
  2. What are the causes, and magnetospheric implications, of two-cell ionospheric convection states that have more flux circulating in the dusk cell than the dawn cell?
  3. How do interplanetary conditions control the degree of rotation of the ionospheric convection pattern and the dawn-dusk asymmetry in flux circulation, and what are the implications for the distribution of nightside reconnection and plasmasheet convection?

This project is funded by a grant from NASA.

Faculty contact: William Lotko