*************************** ** THE GEM MESSENGER ** *************************** Volume 15, Number 2 January 8, 2005 -------------------------------------------------------------------------- Inner Magnetosphere/Storms Assessment Challenge: Defined -------------------------------------------------------------------------- From: Reiner Friedel Richard Thorne Mike Liemohn As a result of our discussions at the GEM 2004 Mini-Workshop at Fall AGU we have settled on the details of our challenge. The main scientific question we need to answer concerns the balance of the loss, transport and acceleration mechanisms for relativistic electrons during storms. To answer this, we need first accurate data (radial PSD profiles in invariant coordinates), for which we also need an accurate "map", i.e. magnetic field, for the storm period. Just having the phase space density gradients alone is not enough - as they represent the NET RESULT of all operating processes - loss & transport & acceleration. Here models are needed. Once a given model can accurately reproduce the observed gradients, then we can ask the model itself to tell us what the roles of loss & transport & acceleration were in the model. The challenge consists of five interlinked parts, applied to two storm periods: 1.) Provide the highest possible fidelity in-situ data for relativistic electrons in the inner magnetosphere. The correct "map" for these measurements is produced in point 2.). 2.) Provide the best possible dynamic magnetic field model: a) Using the PSD matching technique developed at LANL b) Using the T89 modifications developed at FMI c) Other? 3.) Perform model runs for the selected storms. These runs may produce their own global magnetic field or use the provided dynamic fields. 4.) Comparison of particle data between model and data, using the magnetic field coordinate mappings using the best dynamic fields of 2.). Comparison of model-produced magnetic fields with fields of point 2.) . 5.) Output from the models the separate contributions of loss, acceleration and transport. Two storm periods have been selected for this challenge: October 21-23, 2001 September 4-9, 2002 The October 21-23, 2001 has been chosen since it is already being used f or the ring current challenge. The September 4-9, 2002 storm has been chosen for the existence of geosynchronous pitch angle data and because it is not an extreme event. ======================================= We have set up the following communication channels: 1. An email distribution list has been set up by Mike Lienohn (liemohn@umich.edu) for this challenge - gem-radbelt@umich.edu. Please let Mike know of additional people you may want to have added to the list. 2. A web site for the GEM IMS challenge: http://csem.engin.umich.edu/GEM_IMS/ 3. A ftp site for the interchange of data, maintained by Dennis Gallagher ( Dennis.L.Gallagher@nasa.gov): ftp://ftp.nsstc.org/gem. Please contact Dennis to deposit files there, and broadcast your deposit via gem-radbelt@umich.edu. The tasks for point 2.) and 1.) have been done for the September 4-9, 2002 storm, and the data will appear on the site shortly. Initial results are to be presented at the Summer GEM workshop in Santa Fe. Publication plans - A special section of JGR-Space for the GEM-IMS-Challenge results is under discussion, with a September 30, 2005 deadline. For details and further information see http://csem.engin.umich.edu/GEM_IMS/ +-------------------------------------------------------------------------+ |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 | +-------------------------------------------------------------------------+