Table of Contents ====================================================================== 1. 2012 WORKSHOP REPORT: Near-Earth Magnetosphere: Plasma, Fields, and Coupling 2. Three Ph.D-scholarships Available for 2013 Selection in Space Physics Area in Embry-Riddle Engineering Physics Ph.D Program ====================================================================== *************************** ** THE GEM MESSENGER ** *************************** Volume 22, Number 21 August 28, 2012 ---------------------------------------------------------------------- 1. 2012 WORKSHOP REPORT: Near-Earth Magnetosphere: Plasma, Fields, and Coupling ---------------------------------------------------------------------- From: Sorin Zaharia , Stan Sazykin, and Benoit Lavraud, Co-Chairs The goal of this focus group is to improve physical knowledge and modeling capability of the near-Earth magnetosphere (inner magnetosphere and the inner plasma sheet). The focus group held 2 sessions at the 2012 Summer GEM Workshop, its final year of activity. Both sessions took place on Monday, June 18. The first session saw speakers present their latest research results on various topics relevant to the focus group, while the second session was dedicated to short summaries describing research spanning the whole focus group duration, as well as to a discussion of open questions and plans for documenting the focus group activity between 2007 and 2012. Latest Research Results In this session both data-based results and model-derived findings were presented. On the data front, Chih-Ping Wang described near-Earth plasma sheet properties (a crucial driver of inner magnetosphere dynamics), specifically plasma anisotropy, as obtained by a statistical observational study using THEMIS spacecraft data from 2007 to 2010. Focusing on a region closer to Earth, Jerry Goldstein presented remote Energetic Neutral Atom (ENA) imaging from the TWINS satellites. TWINS data (including the low-altitude emission) is an important tool for model validation. Among the questions that the data poses for both theorists and modelers, a prominent one is the physical reason for the observed dawn-dusk asymmetry in pitch angle anisotropy. Finally, Jo Baker analyzed large-scale ionospheric convection features (sub- auroral polarization streams, or SAPS) from SuperDARN HF radar observations. His presentation showcased the unprecedented coverage and resolution of SAPS events observed by mid-latitude radars, making SAPS an excellent opportunity for testing inner magnetosphere models. In fact, his presentation was immediately followed by model results presented by Stan Sazykin, who used the Rice Convection Model (RCM) to simulate several of the observed features. The second part of the session had several model-derived findings presented. Frank Toffoletto and Jian Yang concentrated on the role of entropy "bubbles" and the interchange instability in plasma injection to the inner magnetosphere, using global MHD models (LFM) and the equilibrium version of RCM (RCM-E). Their results reconfirm the crucial role entropy bubbles (whose observed counterpart are the substorm injections) have in ring current formation, as a mechanism for sidestepping the "pressure balance inconsistency." Matina Gkioulidou's presentation highlighted, through simulation results using RCM (with a force balance solver), the importance of ionospheric conductivity (through the e- loss rate/precipitation) in ring current dynamics. A more realistic, MLT-dependent loss rate was also found to lead to better agreement between precipitating electron energy fluxes and statistical DMSP observations. As part of the ongoing quest of improving global MHD model physics, 2 presentations investigated different approaches to this end: 1). Vahe Peroomian presented results using test particles launched in a global MHD code and traced through its fields, results that showed greatly improved agreement with observations during a high speed stream (HSS) geomagnetic storm; 2). Xing Meng presented the latest results in relaxing the isotropy criterion in the BATS-R-US MHD code (anisotropic MHD) and coupling the code with an inner magnetosphere model (CRCM). Finally, Dan Welling's presentation focused not only on the strong effect of ionospheric outflows on near-Earth magnetosphere dynamics, but also on their impact on the magnetosphere shape and the cross polar cap potential (CPCP). While partly verifying the role that a strong ring current has on "inflating" the magnetosphere and reducing CPCP, the results also showed a fundamental difference when ion outflow is introduced, implying that factors other than the magnetopause shape also play a role in the CPCP variation. Summary and Open Questions The second session of the focus group had several groups in the community present, through their representatives, short summaries of their work spanning the focus group duration, and distilling major themes and findings that came up from their work. The strongest such theme, prevalent in all summary presentations, was the importance of including self-consistency between magnetic field and plasma in models of the inner magnetosphere. With one notable exception, the presentations found a self-consistent magnetic field to be a very strong factor in altering inner magnetosphere dynamics, in most cases leading to better agreement with observations. Margaret Chen and Colby Lemon summarized, in 2 separate presentations, inner magnetosphere research at the Aerospace Corporation using the RCM-E model. Their results showed the ring current to be weaker when magnetic (and electric) self-consistency is taken into account, and they also found that the self-consistent RCM-E field compared better than TS04 with observations. Sorin Zaharia summarized inner magnetosphere research performed at Los Alamos in the 2007-2012 timeframe using the self-consistent RAM-SCB model. His results included magnetic field "shielding" (lower ring current pressure) when self-consistency is taken into account, qualitatively similar to the Aerospace RCM-E results. Other RAM-SCB results presented showed a strong dependence of the ring current on the plasma sheet parameters and ion composition, as well as the important effect of the induced electric fields. Matina Gkioulidou presented a summary of her Ph.D. thesis research, which overlapped temporally with the focus group. Using the RCM code with a two-dimensional force balance solver, she also found a strong effect of the self-consistent magnetic field, in particular a weakening of the inner magnetosphere pressure. Of these presentations, Natalia Ganushkina's was the one that did not see significant changes in the computed Dst index with the inclusion of self-consistency. Yet, there were other changes observed: while without self-consistency the tail current had a very strong contribution to the Dst, this relative contribution diminished with the addition of a self-consistent magnetic field. Among the remaining open questions raised and discussed in the context of the summary presentations, the most prominent were: 1). How to include effects of faster time scale processes (e.g. substorms)? 2). How to create, with ever-increasing computational power, more cohesive simulation tools (i.e. replace "coupled" models with global models that take into account relevant physics), and 3). How important exactly is a better model of auroral precipitation? Finally, the final session of the Near-Earth Magnetosphere focus group ended with a discussion about documenting the outcome of the focus group activities between 2007 and 2012. It was agreed that an optimal course of action would be, in addition to the final focus group report, the publication of a review paper detailing the research results obtained under the aegis of the focus group (such a review paper would cite the individual papers published in the relevant timeframe, but could also be accompanied by new papers that would be linked to it). ---------------------------------------------------------------------- 2. Three Ph.D-scholarships Available for 2013 Selection in Space Physics Area in Embry-Riddle Engineering Physics Ph.D Program ---------------------------------------------------------------------- From: Katariina Nykyri The Department of Physical Sciences at Embry-Riddle Aeronautical University (ERAU) at Daytona Beach, FL invites applicants for 2013 Ph.D. graduate study program in the field of space plasma physics. The program includes full funding (20,000 USD stipend plus free tuition), training and education of up to 3 candidates in the fields of space plasma physics, magnetohydrodynamics, and electromagnetism. It focuses on preparation of young scientists for development of comprehensive geophysical models and highly efficient numerical algorithms describing electromagnetic waves and wave-particle interactions in the Earth's magnetosphere and the ionosphere and utilizing and developing techniques for analyzing single and multi-spacecraft data. Students will apply results from their educational/research projects for interpretation of geophysical data collected by ground stations and satellites in several high-profile NASA and NSF programs, such as Space Weather Forecast, Radiation Belts Remediation and Active Ionospheric Experiments. Currently the Aviation and Aerospace Engineering Program at Embry-Riddle is ranked #1 in the USA by US News, and the Physics Department provides excellent conditions for studying modern geophysics including a high-performance computational facility on campus. For further details about ERAU, Physics Department and our Ph.D. program visit http://www.erau.edu and http://daytonabeach.erau.edu/coas/physical-sciences/index.html. For specific questions regarding this program contact Profs. Anatoly V. Streltsov (streltsa@erau.edu) or Katariina Nykyri (nykyrik@erau.edu), Department of Physical Sciences, Embry-Riddle Aeronautical University, 600 S. Clyde Morris Blvd., Daytona Beach, FL 32114, USA. +-------------------------------------------------------------------+ | 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 | +-------------------------------------------------------------------+