Table of Contents ============================================================================ 1. Global-Scale MI Coupling Focus Group (joint session with GGCM) GEM 2007 Summer Meeting (June 18-22, 2007) Zermatt, Utah Contact: David Murr (david.murr@dartmouth.edu) or Mike Wiltberger (wiltbemj@ucar.edu) 2. Global-Scale MI Coupling Focus Group GEM 2007 Summer Meeting (June 18-22, 2007) Zermatt, Utah Contact: David Murr (david.murr@dartmouth.edu) ============================================================================ *************************** ** THE GEM MESSENGER ** *************************** Volume 17, Number 16 June 1, 2007 ---------------------------------------------------------------------------- 1. Global-Scale MI Coupling Focus Group (joint session with GGCM) GEM 2007 Summer Meeting (June 18-22, 2007) Zermatt, Utah Contact: David Murr (david.murr@dartmouth.edu) or Mike Wiltberger (wiltbemj@ucar.edu) ---------------------------------------------------------------------------- From: David Murr Dayside Global Ionospheric Electrodynamics under Varying Solar Illumination (III) With the recent addition of observations from the Iridium constellation of satellites, we now have the capability to make semi-instantaneous global observations of the ionospheric convection (SuperDARN, DSMP, and ground- based magnetometers), field-aligned currents (Iridium), and height- integrated conductances (satellite-based imaging). These combined observations allow us to "challenge" the current set of global MHD codes in way not possible before. This session will be the third in a series that have analyzed magnetosphere - ionosphere coupling during three events with similarly modest and steady IMF driving conditions (IMF Bz~By~ -4 nT), but with differing solar illumination: northern summer-like, equinox-like, and northern winter-like. The prior two sessions have established a baseline of how well the global MHD codes reproduce the observed global parameters of potential, FAC, and conductance. This session will focus on (1) exploring the sources of differences between the models and their abilities to accurately represent MI coupling processes and (2) their ability to represent seasonal effects on energy flow and dissipation. Additionally, we expect discussion that responds to, or follows on from the results and suggestions of Ridley, 2007 (http://www.agu.org/journals/gl/gl0705/2006GL028444/). We solicit contributions from both global MHD and empirical modelers as well as observational groups that can contribute to furthering our understanding of magnetosphere – ionosphere coupling processes during these (or similar) events. Contact David Murr (david.murr@dartmouth.edu) if you would like to participate or if you have and questions or comments. Event Intervals 1. August 04, 2001 12:00-19:00 UT 2. August 31, 2001 00:00-07:00 UT 3. November 18, 2002 00:00-21:00 UT ---------------------------------------------------------------------------- 2. Global-Scale MI Coupling Focus Group GEM 2007 Summer Meeting (June 18-22, 2007) Zermatt, Utah Contact: David Murr (david.murr@dartmouth.edu) ---------------------------------------------------------------------------- From: David Murr Constraints on Reconnection Processes as Derived from Ionospheric Observations: The Expanding and Contracting Polar Cap In addition to playing an active role in modulating magnetosphere - ionosphere coupling, the ionosphere does provide a window onto macro-scale aspects of reconnection processes on the magnetopause and in the magnetotail. To date, improvements in large scale observational capabilities have led to significantly more accurate measurements and characterizations of global ionospheric potentials and flows, field-aligned currents, and height- integrated conductances. This session will explore how these improved observational capabilities can be employed to estimate the macro-scale properties of reconnection processes. Specifically, we will begin the session by highlighting recent advances in estimating dayside and nightside reconnection rates via observations of the time rate of change of the open flux content of the polar cap; in doing so we expect (and encourage) discussions regarding the difficulty in obtaining or the accuracy of measurements of the open/closed boundary. These estimates can be made with the combination of a variety of instrumentation (e.g., space-based or ground-based optical, radar, low-altitude satellite) and we invite and encourage participation from these groups. Additionally, we solicit contributions from global MHD modeling groups regarding how well existing models reproduce observations of the expansion and contraction of the polar cap. We also invite participants that can address how these observations will be or could be enhanced during the THEMIS and/or DASI era. +-------------------------------------------------------------------------+ |To subscribe GEM Messengers, send an e-mail to | | with the following command in the body of your e-mail message: | | subscribe gem | |To remove yourself from the mailing list, the command is: | | unsubscribe gem | | | |To broadcast a message to the GEM community, please contact Peter Chi at | | | |Please use plain text as the format of your submission. | | | |URL of GEM Home Page: http://www-ssc.igpp.ucla.edu/gem/Welcome.html | |Workshop Information: http://gem.rice.edu/~gem | +-------------------------------------------------------------------------+