Table of Contents ====================================================================== 1. 2012 WORKSHOP REPORT: Modes of Magnetospheric Response Focus Group 2. Approval of the SPA Richard Carrington (SPARC) Education and Public Outreach Award ====================================================================== *************************** ** THE GEM MESSENGER ** *************************** Volume 22, Number 24 September 7, 2012 ---------------------------------------------------------------------- 1. 2012 WORKSHOP REPORT: Modes of Magnetospheric Response Focus Group ---------------------------------------------------------------------- From: Larry Kepko , Robert McPherron, and Jenni Kissinger At the 2012 GEM Workshop the Focus Group on Modes of Magnetospheric Response convened two sessions. The first in the morning of Monday June 18 was devoted to new results related to steady magnetospheric convection (SMC) events. The second immediately after lunch considered sawtooth events and other phenomena. In the SMC session N. Ganushkina used Tsyganenko models to demonstrate that during SMC the inner edge of the tail current is located near 10 Re and that there is very little ring current inside of this distance. J. Yang used the Rice Convection Model driven by different boundary conditions in the tail to simulate conditions during an SMC. He found the best match to observations was with a model that has a broad region across the tail where there are localized and transient bursts of reconnection. This suggests that SMC are anything but steady in the tail. A. DeJong described "active SMC" and contrasted them with "classic SMC". During active SMC the level of disturbance in the westward electrojet is much stronger than in typical SMC, and the fluctuations of this electrojet are proportionally elevated. However, the steadiness defined as the ratio of fluctuation amplitude to mean value remains low. Such active SMC can explain the absence of substorm expansions during strong activity. R. McPherron presented an analysis of the synchronous magnetic field during SMC demonstrating that the synchronous field inclination is steadily tail-like throughout the night sector. This result is consistent with the idea that there is a steady current at the inner edge of the plasma sheet distorting the magnetic field. J. Kissinger examined the relation between substorm onset and SMC. She finds that more than 90% of all SMC are immediately preceded by an obvious expansion phase. A more detailed examination reveals that of the remaining 10% all but 1% is preceded by some form of disturbance that may be a poorly observed weak substorm. The small fraction of SMC that cannot be associated with a substorm expansion appear to begin from very quiet conditions. Furthermore, these grow very slowly compared to SMC starting after an expansion phase. The result suggests that for a typical SMC to occur an x-line must form close to the Earth so that continuous transient and localized reconnection at points on the line can balance dayside reconnection. In the afternoon session X. Cai described her extension of the list of sawtooth events to a complete solar cycle. She finds that sawtooth events can occur in both CME and CIR driven storms. The properties of AL and Sym-H during sawtooth events are very different from those during more common types of activity. Jeremy Ouellette relayed results obtained by Oliver Bramble on how sawtooth events can be produced in simulations. Under strong solar wind driving ionospheric O+ is injected into the magnetosphere slowing the reconnection rate. This leads to reduced emission and faster reconnection (substorm expansion). The feedback loop modulates the tail behavior producing a quasi-periodic sequence of substorms. If no O+ is emitted the tail settles into the SMC response mode. It is the combination of strong driving and oxygen emission that converts the SMC mode to the sawtooth mode. J. Baker described new observations from the AMPERE experiment obtained by L. Clausen on the size of the polar cap. During weak solar wind driving the size of the polar cap defined by the ring of Region 1 current expands and contracts in the classic loading-unloading sequence producing a sequence of isolated substorms. In contrast during strong driving the polar cap expands to cover a large area and the changes in its area are small and cannot be identified as individual substorms. A statistical comparison of isolated substorms to SMC events showed the R1 oval size and flux during SMC events were stable compared to the expansion seen at substorm onset. R. Wilder argued that a different mode of activity may occur when the magnetosphere is driven by very strong IMF By. He reported that during these times there is extremely strong Joule Heating in the ionosphere. A. Kellerman reported on his work using Stereo data to predict the arrival of a CIR at the Earth from observations at a spacecraft trailing the Earth in its orbit. Naively one expects that a stream interface will arrive at the speed of corotation of the Sun. In fact the interface may be tilted relative to the ecliptic and may also evolve as the Sun rotates. Errors as large as one day in an expected 3-4 day travel are seen. This makes it very difficult to use the known climatology of a CIR to predict the response of the magnetosphere. A report on the use of magnetometer arrays at opposite end of a field line to study sudden impulses was presented by H. Kim. He found a constant difference between the disturbances in opposite hemispheres that was surprising because it did not depend on day of year. C. Yue carried this theme to the tail where he used Themis data to study the propagation of interplanetary shocks in the tail. ---------------------------------------------------------------------- 2. Approval of the SPA Richard Carrington (SPARC) Education and Public Outreach Award ---------------------------------------------------------------------- From: Nick Gross The AGU Honors and Recognitions Committee has approved the SPARC Education and Public Outreach Award proposed by the SPA Section. This award will be presented to a member of AGU who has had a significant and outstanding impact on students’ understanding and the public's appreciation of SPA science through their education and/or outreach activities. The goal of this award is to recognize members of our community whose educational activities have gone well beyond their particular job title. The first annual SPARC award will be presented at the SPA Dinner during the AGU Fall Meeting of 2012. The award will consist of a $1000 Honorarium, a Framed Award Certificate, and a ticket to the SPA dinner. Members of our community often go well beyond what is expected of them to engage in education and public outreach, for example: include undergraduates and high school students in their research programs, engage members of under-served communities in outreach programs and research projects, develop outstanding citizen science programs, or organize and participate in outstanding outreach programs both nationally and internationally. This award is a way for the SPA section to formally recognize the efforts of these individuals that advances the understanding of what we do as a scientific community. If you know of someone who would be deserving of this award, please consider nominating them. Nominations materials include: Nomination letter or statement, not to exceed two pages, ?with proposed one sentence citation; The nominee's curriculum vitae, not to exceed two pages; Examples with documentation (if available) of nominee's education and outreach activities (up to 3 examples, not to exceed two pages of description total) One additional supporting letter from a third party, not to exceed two pages. The nomination deadline is Oct. 1st. Please send nomination materials to the SPA-EPO Chair, Nick Gross (gross@bu.edu). +-------------------------------------------------------------------+ | 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 | +-------------------------------------------------------------------+