Inductive-dynamic coupling of the ionosphere with the thermosphere and the magnetosphere
Location
Yosemite National Park
Start Date
2-12-2014 5:55 PM
End Date
2-12-2014 6:10 PM
Description
Over the past decades, countless studies have been dedicated to describing the magnetosphereionosphere/ thermosphere coupling and the influences of the magnetospheric variations on the ionosphere/thermosphere system. The models that have been used for practical purposes in global sense are with either a static ionosphere or a height-integrated ionosphere, both of which are not valid or adequate to describe the transient ionospheric processes such as substorms or auroral brightenings. A framework of theory has been proposed and is being developed to self-consistently describe an electromagnetically coupled collisional plasma-neutral system with the inductive and plasma as well as neutral dynamic effects. In this presentation, we describe the new approach of multi-fluid inductive dynamic magnetosphere-ionosphere-thermosphere (MID-MIT) coupling, in which ions and neutrals are treated dynamically as multiple fluids. The magnetic field can vary with time and in space: its temporal variations induce electric field and its spatial variations produce currents. The conventional concepts of mapping the electric potential, magnetic field, and field-aligned currents become invalid during the dynamic stage. We compare the differences between this inductive-dynamic theory and the conventional magnetosphere-ionosphere/thermosphere coupling mechanisms. The inductive-dynamic theory shows that the transition for the ionosphere to respond to a magnetospheric change lasts for about 20-30 min, the critical time scale for most of ionospheric dynamic processes. During the transition period, large-amplitude fluctuations, enhanced heating, and upward flow are expected and present in one-dimensional numerical simulations.
Inductive-dynamic coupling of the ionosphere with the thermosphere and the magnetosphere
Yosemite National Park
Over the past decades, countless studies have been dedicated to describing the magnetosphereionosphere/ thermosphere coupling and the influences of the magnetospheric variations on the ionosphere/thermosphere system. The models that have been used for practical purposes in global sense are with either a static ionosphere or a height-integrated ionosphere, both of which are not valid or adequate to describe the transient ionospheric processes such as substorms or auroral brightenings. A framework of theory has been proposed and is being developed to self-consistently describe an electromagnetically coupled collisional plasma-neutral system with the inductive and plasma as well as neutral dynamic effects. In this presentation, we describe the new approach of multi-fluid inductive dynamic magnetosphere-ionosphere-thermosphere (MID-MIT) coupling, in which ions and neutrals are treated dynamically as multiple fluids. The magnetic field can vary with time and in space: its temporal variations induce electric field and its spatial variations produce currents. The conventional concepts of mapping the electric potential, magnetic field, and field-aligned currents become invalid during the dynamic stage. We compare the differences between this inductive-dynamic theory and the conventional magnetosphere-ionosphere/thermosphere coupling mechanisms. The inductive-dynamic theory shows that the transition for the ionosphere to respond to a magnetospheric change lasts for about 20-30 min, the critical time scale for most of ionospheric dynamic processes. During the transition period, large-amplitude fluctuations, enhanced heating, and upward flow are expected and present in one-dimensional numerical simulations.