Table of Contents ====================================================================== 1. Workshop Report: Space Radiation Climatology Focus Group 2. Workshop Report: Radiation Belts and Wave Modeling Focus Group ====================================================================== *************************** ** THE GEM MESSENGER ** *************************** Volume 21, Number 26 October 7, 2011 ---------------------------------------------------------------------- 1. Workshop Report: Space Radiation Climatology Focus Group ---------------------------------------------------------------------- Conveners: Paul O'Brien and Geoff Reeves At the summer 2011 GEM workshop, the Space Radiation Climatology focus group held 2 sessions on Wednesday, June 29th. A detailed agenda, many of the talks, and links to data and models can be found at http://www.virbo.org/GEM_FG9_2011. In our first session, our first scheduled talk, a summary of progress over the life of the focus group, was cancelled because the speaker, Reiner Friedel was occupied with the fire in Los Alamos. We heard from Xinlin Li about the behaviors of MeV electrons at geosynchronous orbit during different phases of the solar cycle, and, in particular, about several major climatological features of the radiation belts that are reproduced fairly well by his solar-wind driven model. Natalia Ganushkina present results of a survey of the locations of the inner and outer boundaries of the inner and outer radiations belts, and how they have evolved over multi-year timescales. Interestingly, this study was the result of examining the backgrounds in plasma instruments on Cluster and Double Star. Richard Denton announced the posting on-line of his mass density database for geostationary orbit for 1980-1991. Yuri Shprits gave us an update on the progress of the UCLA/VERB code. Geoff Reeves wrapped up our first session with a discussion, motivated by the results of his recent paper revisiting the most famous radiation belt climatology result: Paulikas and Blake's correlation of average electron flux at GEO with solar wind speed. From these talks, we learned that the climatology of the radiation belts is richer than most had assumed, and we are just beginning to determine which of those climatological features we can reproduce and sometimes explain with our models. In our second session, we focused a bit more on the nitty gritty of doing radiation belt science. Dave Byers provided an overview of the NRO's project to develop AE9/AP9 radiation belt climatology models. Dmitri Kondrashov discussed some performance improvements one can obtain by splitting the diffusion operators. This procedure offered significant speed gains, and worked well in the context of data assimilation, even though it required some simplification of the physics (e.g., no off-diagonal terms in the diffusion tensor). Steve Morley valiantly presented several topics on behalf of his missing LANL colleagues. Included in his presentation were some validation results from comparing different L* (third invariant) calculations with different software libraries, a discussion of the ring current module in LANL's DREAM model (for those who recall the MSM and RCM, this presentation brought back many old memories). Also, Steve described SpacePy, an open-source Python tool set for space scientists. Paul O'Brien described a related set of tools that are part of the "extras" in the open-source IRBEM library at sourceforge. We concluded with an advertisement for Geoff Reeves’ Radiation Belt Science Blog http://web.me.com/greeves/rbsci/Whats_New/Whats_New.html, where he posts updates on NASA's RBSP mission, GEM Focus groups, and everything else. This was the final year of the Space Radiation Climatology focus group. While we did not achieve all of our objectives, we made good progress on many fronts. ---------------------------------------------------------------------- 2. Workshop Report: Radiation Belts and Wave Modeling Focus Group ---------------------------------------------------------------------- Conveners: Yuri Shprits, Scot Elkington, Jacob Bortnik, and Craig Kletzing The GEM Radiation Belt and Waves (RBW) focus group held a series of productive discussions and presentations at the June 26 - July 1 2011 joint GEM/CEDAR Workshop in Santa Fe, New Mexico. Topics covered wave-particle interactions and the dynamical evolution of the radiation belts, remote sensing, and global modeling of radiation belt dynamics. The RBW focus group held a session on Monday, June 26, to discuss and finish formulating a global radiation belt modeling challenge. The intent of the challenge is to better understand the relative strengths of available physical and analytical models in capturing global radiation belt dynamics, defining necessary data inputs and model requirements, and working towards defining appropriate comparative metrics in evaluating the various models. The period selected for the challenge encompasses February 1, 1991 to July 31, 1991, with a prior 'training period' for analytic models. UCLA, Aerospace Corp, AFRL and others information about the RBW global radiation belt challenge is available at http://virbo.org/rbw. A session was devoted to new results and understanding in the dynamical evolution of the radiation belts. Among the findings discussed in this session was new observational evidence that outward radial transport and losses to the magnetopause play and important role in the dynamics of the radiation belts. Adiabatic effects at low altitudes, whereby variations in the particle mirror point in response to changes in the global field configuration, were also considered in the context of flux dropouts observed at LEO. Discussions were held on the occurrence of ELF, magnetosonic, and whistler-mode VLF waves, and their effect on particle diffusion rates. A joint session with CEDAR was organized to discuss remote sensing of the radiation belts, and how these techniques could further our understanding of relevant physical processes in these regions. The session focused on ULF and VLF ground measurements, TEC reconstructions, and balloon and riometer measurements of energetic particle precipitation. The RBW group focused on wave-particle interactions in a Thursday session, and included topics in EMIC wave measurement, computation of diffusion coefficients using qusilinear theory and particle simulations, and properties of magnetospheric plasma waves. There was general agreement on the need to combine multiple satellite measurements to obtain detailed statistical maps of wave occurrence in the magnetosphere. The RBW sessions wrapped up on Friday with a discussion of simulations and observations of chorus and hiss waves. THEMIS observations show that rising chorus elements are predominantly field-aligned while falling tones are oblique and weaker, each associated with different MLT and latitudinal distributions suggesting different mechanisms generation mechanisms for rising and falling tones. We also discussed PIC and ray tracing simulations of magnetospheric chorus waves, and how these techniques could augment our understanding of radiation belt dynamics. Participation in the RBW sessions at GEM was high, and underscored the level of scientific activity in this field of research. We look forward to continued advancements in our understanding of radiation belt and wave dynamics under the auspices of the GEM program during the upcoming era of the NASA RBSP mission. +-------------------------------------------------------------------+ | 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. | | | | GEM Messenger is also posted online via newsfeed at | | http://heliophysics.blogspot.com and | | http://www.facebook.com/heliophysics | | | | Back issues are available at ftp://igpp.ucla.edu/scratch/gem/ | | | | URL of GEM Home Page: http://aten.igpp.ucla.edu/gemwiki | | Workshop Information: http://www.cpe.vt.edu/gem/index.html | +-------------------------------------------------------------------+