<div dir="ltr"><div>***************************</div><div> THE GEM MESSENGER</div><div>***************************</div><div><br></div><div>Volume 27, Number 40</div><div>Aug.28,2017</div><div><br></div><div>Announcement submission website: <a href="http://aten.igpp.ucla.edu/gem/messenger_form/">http://aten.igpp.ucla.edu/gem/messenger_form/</a></div><div><br></div><div>============================================================</div><div>Table of Contents</div><div><br></div><div>1. 2017 GEM Workshop Report: Quantitative Assessment of Radiation Belt Modeling Focus Group</div><div><br></div><div>============================================================</div><div><br></div><div>------------------------------------------------------------</div><div>1. 2017 GEM Workshop Report: Quantitative Assessment of Radiation Belt Modeling Focus Group</div><div>------------------------------------------------------------</div><div>From: Weichao Tu, Wen Li, Jay Albert, and Steve Morley (Focus Group Leaders) (wetu at <a href="http://mail.wvu.edu">mail.wvu.edu</a>)</div><div><br></div><div>In the 2017 GEM Summer Workshop, “Quantitative Assessment of Radiation Belt Modeling” (QARBM) Focus Group held four sessions on Wednesday June 21st and Thursday June 22nd. All of the sessions were well-attended with helpful discussions. There were 39 scheduled short talks over the 4 sessions, covering a wide range of topics, as listed below:</div><div><br></div><div>Session 1 - “Observations of radiation belt processes”</div><div><br></div><div>In the first session ten talks were presented on the observational studies of the dynamical processes in the radiation belts based on the long-term Van Allen Probes data and the new data from MMS, Lomonosov, etc. The session starts with three presentations on the long-term or statistical studies of radiation belt electrons, with topics including: the long-term perspective on outer belt electrons by comparing Van Allen Probes era with the previous two solar cycles, untangling the solar wind drivers of radiation belt using an information theoretical approach, and statistical studies on the peaks in electron phase space densities. Then the following three talks focused on the observed loss of radiation belt electrons, including detailed event studies on the radiation belt dropouts observed by Van Allen Probes to understand the underlying loss mechanisms, studies showing new signatures of ultrarelativistic electron loss in the heart of the Earth's radiation belts, and new observations of electron precipitation by the ELFIN-L instrument on Lomonosov Spacecraft. The remaining four talks in the session discussed the observed properties of various magnetospheric waves, including the statistics of low frequency hiss, estimation of the plasmasphere electron densities from hiss wave observations, the phase coherency scales of individual chorus elements and the greater chorus active region observed by Van Allen Probes and MMS, and EMIC waves observed by the Van Allen Probes.</div><div><br></div><div>Session 2 - “Modeling of local processes and transport”</div><div><br></div><div>This session focused on various plasma excitations and their detailed effects on energetic electrons. Oscillations in electron flux seen by Van Allen Probes were shown and analyzed in terms of radial diffusion processes, presumably driven by ULF waves. One talk focused on the loss of relativistic and ultra-relativistic radiation belt electrons using quasi-linear diffusion by EMIC waves, while in another talk transport coefficients for EMIC waves were obtained directly from test particle simulations and used in a modified Fokker-Planck equation. A three-wave coupling mechanism for the generation of highly oblique chorus waves was presented, and other talks treated diffusion coefficients for such waves computationally and analytically. Particle-in-cell (PIC) simulations of the generation of magnetosonic waves were shown, as were LAPD and PIC findings of electrostatic waves generated along with whistler-mode waves. Finally, broadband electrostatic turbulence was discussed and interpreted as phase space electron holes, and diffusion coefficients analogous to those for upper band chorus waves were presented.</div><div><br></div><div>Session 3 - “Global modeling, metrics and validation”</div><div><br></div><div>This session was joint with the “Modeling Methods and Validation” FG. There were eleven presentations, with discussion emphasizing the need for metrics and validation methods that can be used to quantitatively assess the global modeling of radiation belt dynamics. The session started with an overview talk on the global radiation belt modeling, metrics and validation, an introduction on the existing and new measures of model performance, and a brief comparison between the different metrics. Following those metrics talks, modelers presented their new modeling results and expressed their interests in testing those proposed metrics with their results. One talk presented the global validation of the reduced Fokker Planck computations of radiation belts dynamics. Two talks discussed the newly developed magnetic field models, including the latest TS07D model and the event-specific magnetic field models by fitting to in-situ data. On the simulation of the radiation belt dynamics, one talk focused on simulating the electron precipitation loss observed by multiple NOAA POES satellites using a drift-diffusion model; one talk used the MHD-test particle simulation to simulate the prompt electron acceleration by the 17 March 2015 interplanetary shock; and the remaining three talks simulated the global dynamics of radiation belt electrons based on various Fokker-Planck models, such as the CIMI model with new applications of whistler wave distribution models, the UCLA 3D diffusion model in modeling diffusive transport of 100s keV electrons in the slot region, and the long-term VERB code simulation with parametrized EMIC waves.</div><div><br></div><div>Session 4 - “New challenge results and plans”</div><div><br></div><div>The final session consists of nine presentations and extensive discussion focusing on new results from multi-satellite observations and “QARBM” challenge events. One talk showed the statistical study of spatial extent of relativistic electron precipitation, and another talk discussed a statistical examination of favorable plasma conditions concerning EMIC wave excitation. Interesting wave characteristics were also presented including Langmuir waves modulated by rising-tone chorus, response of whistler mode waves to interplanetary shocks, and whistler wave growth during ICME and CIR-driven storms. Two other talks discussed the construction of electron density in the inner magnetosphere using neural network. Recent updates on the quantitative assessment of “QARBM” challenge events were presented for the “dropout” and “enhancement” events respectively. The final presentation of the session also provided an overview of the existing community resources for the challenge events, followed by an open discussion on the missing resources for the challenge events, approaches to assess modeling results with various metrics, and plans for FG activities over the next year.</div><div><br></div><div><br></div><div>========================================</div><div>The Geospace Environment Modeling (GEM) program is sponsored by the Division of Atmospheric and Geospace Sciences (AGS) of the National Science Foundation (NSF).</div><div><br></div><div>To broadcast announcements to the GEM community, please fill out the online request form at:</div><div><br></div><div><a href="http://aten.igpp.ucla.edu/gem/messenger_form/">http://aten.igpp.ucla.edu/gem/messenger_form/</a></div><div><br></div><div>To subscribe to the newsletter, please go to the web page at:</div><div><a href="http://lists.igpp.ucla.edu/mailman/listinfo/gem">http://lists.igpp.ucla.edu/mailman/listinfo/gem</a></div><div>(IMPORTANT: Do not use this web page to post announcements.)</div><div><br></div><div>For any other questions, please contact Peter Chi, GEM Communications Coordinator, at <pchi at <a href="http://igpp.ucla.edu">igpp.ucla.edu</a>></div><div><br></div><div>URL of GEM Home Page: <a href="http://aten.igpp.ucla.edu/gemwiki">http://aten.igpp.ucla.edu/gemwiki</a></div><div>Workshop Information: <a href="http://www.cpe.vt.edu/gem/index.html">http://www.cpe.vt.edu/gem/index.html</a></div><div>========================================</div><div><br></div>
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