Table of Contents ============================================================================ 1. Prospectus for a "Geospace System" Focus Group: Call for Participation Friday, June 26, 10:30-12:15 2. GEM "GGCM Methods and Modules" Focus Group: Call for Participation 3. Solicitation of Contributions to the 2009 GEM Session on "Bow Shock Phenomena and their Magnetospheric Impacts" ============================================================================ *************************** ** THE GEM MESSENGER ** *************************** Volume 19, Number 10 May 19, 2009 ---------------------------------------------------------------------------- 1. Prospectus for a "Geospace System" Focus Group: Call for Participation Friday, June 26, 10:30-12:15 ---------------------------------------------------------------------------- From: Bill Lotko and George Siscoe We would like to initiate a discussion among the magnetospheric and aeronomy communities (portions, at least) on the prospect of undertaking a global, system-dynamics study of the coupled solar wind-magnetosphere-ionosphere- thermosphere system, which we identify simply as the geospace system. The suggestion responds to two circumstances: first, 50 years of magnetospheric research have shown the geospace system to be interactively coupled in multiple ways from the solar wind to the thermosphere, and second, as GEM moves in its long-range program from the 'divide-and-conquer' stage to the more challenging synthesis stage, a focus group devoted to problems of the coupled system will leverage scientific progress in each GEM research area. The magnitude of the task to comprehend the global system in its coupled complexity is almost certainly too great for a single, scientist-centered research team and probably too great for the multiple teams of a single institution. Instead it would seem to require a sustained collaborative effort by experts of manifold specialties distributed among many institutions. It might even take the combined collaboration of the GEM community and a sizable portion of the CEDAR community. The priorities of such a focus group must be enlightened by community interest. To begin the conversation we can suggest among many possible directions several problems, each global in scope and of considerable current interest. We have asked some GEM participants to help initiate the discussion with a few slides on each problem. They include: 1) the dayside reconnection potential, its relationship to the polar cap potential, and the saturation of both at large IMF; 2) global resonance, periodicity of the magnetospheric response, and sawtooth phenomena; 3) ionospheric- magnetospheric plasma circulation, including ionospheric outflows, and its effects on plasmasheet and inner magnetospheric dynamics; and 4) prompt penetration electric fields and their relationship to the dayside ionospheric superfountain, storm enhanced density, and plasmaspheric plumes. While some aspects of these global problems can be treated as regional phenomena, differentiated by distinct physical processes, their dynamics seem to evolve as an integrated whole during extreme solar wind conditions. The geospace system thus behaves coherently across a broad spatiotemporal range, making it difficult to unravel its causal behavior by considering the response in terms of isolated elements or processes. Integration of global problems of this type into a system-dynamics picture spans the expertise of all five GEM research areas and several CEDAR working groups. We invite participation from the GEM community in deciding whether the time is right for this focus group, and, if so, how best to structure its direction. ---------------------------------------------------------------------------- 2. GEM "GGCM Methods and Modules" Focus Group: Call for Participation ---------------------------------------------------------------------------- From: John Dorelli The GGCM Methods and Modules Focus group would like to invite participants to two sessions to be held at the summer GEM workshop in Snowmass June 21-26. Both sessions will be held Wednesday, June 24: Session 1 (10:30 am): What role does electron dissipation play in open boundary condition simulations of magnetic reconnection? In this session, we would like to continue where we left off last year, addressing the following issues: 1. What is the role of secondary magnetic islands? Are they an irrelevant by-product, or do they play an essential role in determining the aspect ratio of the dissipation region? 2. What limits the aspect ratio of the electron dissipation region? 3. How does the reconnection rate scale with dissipation scale parameters (e.g., resistivity or electron mass) in simulations (electron MHD, Hall MHD, hybrid, fully kinetic)? Session 2 (1:30 pm): How do we accurately model magnetospheric reconnection on a global scale? Topics for this session include: 1. How does the physics of reconnection depend on the ad hoc resistivity model used in global MHD codes? In particular, how does reconnection scale with resistivity in the high Lundquist number limit? What is the effect of numerical resistivity? Can we reproduce Petschek reconnection by localizing the plasma resistivity? What is the effect of current dependent resistivity? 2. How does dayside magnetopause reconnection work in global MHD codes? Is reconnection locally controlled or externally driven? Does the Cassak- Shay formula apply to the dayside magnetopause? 3. What is the status of global Hall MHD modeling? What are the most robust numerical approaches? What are the new results coming from the latest generation of global Hall MHD magnetosphere codes? 4. What is the status of other non-MHD approaches to global magnetosphere modeling (e.g., global hybrid codes)? Are there any new ideas on the horizon? If you are interested in participating in either of these sessions, please email one of the focus group co-chairs: john.dorelli at nasa.gov or brian.sullivan at unh.edu. ---------------------------------------------------------------------------- 3. Solicitation of Contributions to the 2009 GEM Session on "Bow Shock Phenomena and their Magnetospheric Impacts" ---------------------------------------------------------------------------- From: N. Omidi , D. Sibeck During the 2009 GEM Summer workshop at Snowmass Colorado, a session on the bow shock and its magnetospheric impacts will be held on Monday June 22nd. This marks the last year of the Bow Shock Focus Group and in addition to discussion of recent observations, modeling, and theory of the bow shock and related processes in the foreshock and the magnetosheath we will discuss future plans. In particular, N. Omidi will provide a summary of accomplishments and current status and D. Sibeck will discuss future missions followed by solicitation and discussion of ideas about future directions and plans. Those who are interested and wish to show a few relevant slides are invited to contact the conveners omidi@solanasci.com, David.G.Sibeck@nasa.gov. For updated information please see http://www.cpe.vt.edu/gem/index.html . +-------------------------------------------------------------------------+ |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://aten.igpp.ucla.edu/GemWiki | |Workshop Information: http://www.cpe.vt.edu/gem/index.html | +-------------------------------------------------------------------------+