Role of Ionosphere in Substorm Dynamics

Abstract:

Earth's ionosphere and magnetosphere are closely coupled, such that
ionosphere conductance partially controls magnetospheric convection.
In the extreme case of infinite conductance, field lines are tied in the
ionosphere and magnetospheric convection is completely suppressed,
after some transition period. In the opposite case, i.e., a non conducting
ionosphere, magnetosphere convection would be controlled by magnetospheric
processes alone. The reality lies somewhere in between and it can thus be
expected that the substorm cycle may also be influenced by ionospheric conditions.
Furthermore, since the state of the magnetosphere feeds back on the ionosphere
via particle precipitation, a positive feedback could lead to intrinsic instability
of the magnetosphere - ionosphere system. Here, we use OpenGGCM simulations
to investigate how the magnetosphere reacts to variations in the ionosphere
parameters and and if the feedback is sufficiently strong to create an
instability.