*************************** ** THE GEM MESSENGER ** *************************** Volume 14, Number 15 May 10, 2004 ------------------------------------------------------------------------- Call for Participants: GEM MI Coupling Working Group 2 on Electrodynamics ------------------------------------------------------------------------- From: William Lotko and Joshua Semeter GEM MI Coupling Working Group 2 on electrodynamics for the 2004 Summer GEM Workshop in Snowmass, Colorado June 23-25 Co-Chairs: William Lotko and Joshua Semeter GEM Meeting website: http://gem.rice.edu/~gem Working Group 2 will host a tutorial by Dr. Chris Chaston from UCB/SSL entitled: "Alfvenic Acceleration Processes in MI Coupling" and 3 breakout workshop style sessions focused on the questions listed below. If you would like to participate in any of these sessions, please contact one of us. Breakout 1. Beyond the Knight relation --------------------------------------- This breakout concerns the physics governing the transition between thermal and nonthermal plasmas in the ionosphere and magnetosphere. Observational evidence suggests that several distinct mechanisms contribute to accelerating auroral particles (e.g., Alfven waves, mirror force, electrostatic turbulence, transverse ion heating), but their relative importance in affecting electrodynamic MI coupling remains unclear. How such kinetic processes can be parametrically embedded within global models to give meaningful predictions of fluxes and rates also remains at issue. This year, the discussion will focus primarily on acceleration in the downward current region, with the overarching goal of determining whether a parametric description (i.e., a Knight-type relationship) of this important return current region is possible. Breakout 2. Ionosphere-Magnetosphere Feedback --------------------------------------------- Since Atkinson first proposed that positive feedback between the ionosphere and magnetosphere could contribute to auroral formation, much detailed modeling work has been done to refine and expand on this concept. Ionospheric feedback and, more generally, Alfvenic resonant modes have been used to address the complete hierarchy of spatial and temporal scales observed in auroras, field aligned currents, and Poynting flux. Observational evidence for these models, however, remains indirect and incomplete. This breakout we will focus on the state of research on feedback mechanisms in MI coupling, with specific emphasis on methodologies to link observations and modeling in a meaningful way. Similar to the previous breakout, we are ultimately interested in the extent to which such feedback interactions regulate large-scale processes. Breakout 3. Global-scale asymmetries in MI coupling --------------------------------------------------- Synoptic measurements of high-latitude electromagetic fields, currents, and auroras have revealed both longitudinal and hemispheric asymmetries. Such global-scale MI coupling effects should be predicted by global models, yet many fundamental questions remain. For example, can asymmetries in auroral intensity and morphology be accounted for as the IMF influence on the magnetospheric configuration and tilt angle? How well are these effects incorporated in magnetic field models? Does the state of the ionosphere play a role, for example, in observed dayside/nightside asymmetries in Joule heating. Which is more important in the development of non-conjugate phenomena, seasonal conductance differences or interplanetary magnetic field orientation? +-------------------------------------------------------------------------+ |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 | +-------------------------------------------------------------------------+