[GEM] THE GEM MESSENGER, Volume 26, Number 36

[Newsletter Editor]

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     THE GEM MESSENGER
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Volume 26, Number 36
Sep.11,2016

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Table of Contents

1. GEM Meeting Coordinator Search

2. 2016 GEM-CEDAR Workshop Report: Quantitative Assessment of Radiation Belt Modeling Focus Group

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1. GEM Meeting Coordinator Search
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From: Michael Wiltberger (wiltbemj at ucar.edu)

GEM Meeting Coordinator Search

The GEM meeting coordinator plays an important role in ensuring that our community has a successful meeting each year.  The current grant for running the meeting expires in 2018 and while that may seem a long time in the future we are currently working on getting the location of the 2018 meeting finalized.  This means that it is time starting search for a meeting coordinator.

As mentioned, the main role of the meeting coordinator is to work with the steering committee to run the annual GEM meeting.  Key responsibilities include; proposing for and managing the award from NSF for the meeting support; soliciting bids from hotels, resorts, managing the contracts for meetings, and coordinating the travel for students supported by the grant to attend the meeting.  We expect strong communication between the GEM chair and meeting coordinator, complete transparency and the ability to independently research, negotiate and secure conference venues on behalf of the GEM steering committee in a timely manner.  In past, meeting coordinators have found it helpful to have strong administrative support in order to handle these tasks.  The meeting coordinator automatically becomes a full voting member of the GEM steering committee and has a voice in setting the strategic direction of GEM.

Anyone interested in serving, as the meeting coordinator should prepare a short, 1 page maximum, statement of his or her qualifications and interest in the position.  It should include their plan for managing the key responsibilities, vision for working with the steering committee and a rough estimate of costs. Based on these statements of interest, the GEM Steering Committee will select and appoint the meeting coordinator for the next 5-year period.  Final instatement of the meeting coordinator rests with the NSF, and is accomplished through an award from the GEM program for managing the annual meeting.  These letters need to received by November 28th in order to allow the GEM SC evaluate them at GEM steering committee meeting following the min0GEM meeting.

Any questions about the position can be directed to SC chair Mike Wiltberger (wiltbemj at ucar.edu) or Vice-Chair Jacob Bortnik (bortnik at atmos.ucla.edu)


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2. 2016 GEM-CEDAR Workshop Report: Quantitative Assessment of Radiation Belt Modeling Focus Group
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From: Weichao Tu, Wen Li, Jay Albert, and Steve Morley (wetu at mail.wvu.edu)

In the 2016 GEM Summer Workshop, “Quantitative Assessment of Radiation Belt Modeling” (QARBM) Focus Group held four sessions on Tuesday June 21st, Wednesday June 22nd, and Friday June 24th. All of the sessions were well-attended with helpful discussions. There were 41 scheduled talks in total and a few walk-in talks over the 4 sessions, covering a wide range of topics, as listed below:

Session 1 - “Radiation Belt (RB) particles and modeling”

In the first session thirteen talks were presented on the observational and modeling results for the acceleration, transport, and loss of radiation belt particles. The session starts with five observational study talks covering topics of: the statistical relation between radiation belt electrons and solar wind parameters/geomagnetic indices based on the Van Allen Probes data, long-term comparison of the radiation belt electron variations between the Van Allen Probes era and previous two solar cycles, the secular drift of the SAA using the SAMPEX proton data, the source of inner zone electrons by sudden injections observed by Van Allen Probes, and the near-instantaneous energization of radiation belt electrons by IP shocks during the 17 March 2015 event. The following eight talks reported recent modeling studies on various topics, including: simulations of ULF wave-driven transport, energization, loss of RB electrons during the 17 March 2013 & 2015 storms using the LFM/MHD results combined with a radial diffusion model; modeling the seed population of the radiation belts with the LANL SHIELDS modeling framework; recent development and forecast performance of the data-assimilative VERB code; CCMC modeling results (using SWMF+RCM+RBE) for the RB "dropout" and "buildup" challenge events organized by our FG (with more covered in Session 4); modeling of dropout and drift loss to the magnetopause using CIMI model for the challenge event on 1 June 2013; response of radiation belt simulations to different radial diffusion coefficients using the 3D VERB code; a review of the recent modeling work on electron dropouts; and a data/modeling integration of the non-linear acceleration of RB electrons by VLF chorus rising tones.

Session 2 - “Waves and local interactions”

This session consists of thirteen talks which were focused on characterizing various wave properties and plasma conditions that are required as inputs to RB models. We started with quantifying the ULF wave radial diffusion coefficients using global ground based magnetometer measurements, followed by reproducing the observed energy-dependent structure of electron radiation belts during storm recovery with an event-specific diffusion model. Then two talks were presented regarding constructing the plasma density evolution on the global scale using neural network. The following five talks discussed interesting characteristics of whistler mode chorus waves including their frequency spectra, polarization properties, coherent scale size, and saturation characteristics. Subsequently, three talks were presented regarding EMIC waves including the statistical distribution using Van Allen Probes data, modeling EMIC wave properties using linear theory and hybrid simulation, and evaluation of electron scattering caused by observed EMIC waves. At last, an interesting talk was presented regarding nonlinear local parallel acceleration and precipitation of electrons by oblique whistler-mode waves.

Session 3 - “ULF waves and nonlocal transport”

This session was joint with the “ULF Wave Modeling, Effects, and Applications” FG. There were 8 presentations, with discussion emphasizing the need for data-model comparisons – e.g., validating diffusion coefficients with event-specific wave measurements. Radial diffusion in non-dipolar fields was discussed, and found to lead to faster outward radial transport than standard results. Observations and test particle simulations of outer belt electron radial transport were presented for ULF waves with varying properties – m number, monochromatic versus broadband frequency spectrum – producing very different types of radial transport/radial PSD profiles. The importance of pitch angle dependence on radial diffusion and the calculation of diffusion coefficients was discussed, comparing results from 3 simulations (with different assumptions for wave activity) plus observations for the 17 Mar 2015 event. Diffusion simulation results were presented indicating that drift shell splitting effects and a fully 3D diffusion matrix can reduce electron PSD enhancements during storms. A simulation was shown of the radial intrusion and slow decay of energetic electrons in the Earth's slot region by incorporating radial diffusion transport and hiss-induced pitch angle scattering processes. RBSP and Arecibo ISR E-field measurements near L=1.4 were shown; electric fields were consistent with plasma sub-corotation and could be included in future diffusion coefficient calculations. The role of ULF waves in high energy particle acceleration in the auroral acceleration region was presented, with future application of the theory to particle acceleration in the Earth’s radiation belts. A statistical study of the azimuthal wave number associated with globally coherent ULF waves was discussed, using ground magnetometer measurements. 

Session 4 - “RB "dropout" and "buildup" challenges and future plans”

The final session featured seven presentations, and extensive discussion, focusing on the four challenge events chosen for this focus group. The first presentation highlighted the importance of the choice of parameterization for diffusion processes in radiation belt modeling. The following five talks all targeted the challenge events specifically: a study of the formation of the inner electron belt during the storm-time enhancement challenge event (2013 St. Patrick’s Day storm); event-specific wave parameters and diffusion coefficients; calculations of the last closed drift-shell; and distributions of law-altitude electrons during the chosen events. The final presentation of the session gave an overview of the community resources for the challenge events - links to the community resources curated by the focus group, including readme files and overview presentations for the challenge events, can be found from the QARBM focus group page on the GEM wiki.  The session concluded with discussions of: 1. the inputs, boundary conditions and verification data that the community felt were required for quantitative and comparative modeling of the challenge events, and 2. the approach to coordinating study of the challenge events over the next year.


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