CEDAR Report:

CEDAR and GEM Magnetosphere-Ionosphere Coupling Campaigns

During this past June, both the CEDAR and GEM communities devoted their attention to a new collaborative research activity devoted to improving our understanding and specification of the role of the ionosphere and ionospheric plasma in the coupled magnetosphere-ionosphere system. Important consequences of this research apply not only to the electrodynamic coupling of the current systems that flow between the magnetosphere and ionosphere, but also to the mechanical coupling between the thermosphere and ionosphere and its impact on global wind systems.

At CEDAR, there was a two-hour workshop in which more than 60 scientists and students participated. Eleven speakers gave brief presentations on issues they believed to be of importance. One issue that arose repeatedly was the detailed current-voltage-conductance relationships that exist in the high-latitude ionosphere. It was recognized that our detailed understanding of these relationships, at scale sizes down to that of an auroral arc, is not very good. This issue is of importance for understanding closure of magnetospheric current system and also for understanding a closely related quantity, Joule heating. A. Richmond discussed how AMIE modeling might help in these studies, but noted that AMIE estimates vary with the data inputs. He stated that the AMIE procedure could be used to examine the consistency between various inputs. Several other speakers, R. Smith, J. Thayer, and G. Crowley, discussed related issues on the importance of understanding Joule heating and its impact on the global ionosphere and atmosphere. J. Foster and B. Fejer discussed the impact of high-latitude electric fields penetrating to lower latitudes and severely affecting the mid-latitude and even low-latitude ionosphere. In particular, J. Foster noted evidence of significant outflow of ionospheric plasma into the magnetosphere. There were also discussions on the impact of electric fields on plasma instability excitation and consequential impacts on ionospheric structure, electron heating and composition changes.

At GEM, there were nearly 12 hours of meetings involving two MI Coupling Working Groups directed toward the topics of "Ionospheric Plasma in the Magnetosphere" and "Electrodynamics of MI Coupling". The former group is concerned with the effects of outflowing ionospheric plasma on the magnetosphere. The latter group is concerned with the details of how mid-altitude plasma processes structure the current systems connecting the magnetosphere and ionosphere. Each group identified 3 challenge areas:

Ionospheric Plasma in the Magnetosphere

  1. Mass Exchange Characterization
  2. Impacts of Ionospheric Plasma
  3. Mass-Extraction Process Modeling
Electrodynamics of M-I Coupling
  1. Ionospheric Conductance

  2. Auroral Plasma Energization

  3. Multi-scale Processes

Overall, it would seem that there are many areas of common interest between CEDAR and GEM researchers. Quite possibly this collaborative research opportunity could prove enlightening and rewarding to both communities. The first opportunity to propose for this new research activity should be announced in the near future.