Table of Contents ====================================================================== 1. 2013 GEM Tutorials Are Available at GemWiki 2. 2013 Workshop Report from Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures Focus Group (FG) ====================================================================== *************************** ** THE GEM MESSENGER ** *************************** Volume 23, Number 29 September 17, 2013 ---------------------------------------------------------------------- 1. 2013 GEM Tutorials Are Available at GemWiki ---------------------------------------------------------------------- From: Peter Chi The following tutorial talks presented at the 2013 Summer Workshop are now available online at http://aten.igpp.ucla.edu/gemwiki/index.php/GEM_Tutorials. 1. Andrei Runov - Magnetotail Transients 2. Michael Shay - Magnetic Reconnection at the Dawn of the MMS Era 3. Harlan Spence - Recent Science Results from NASA Van Allen Probes 4. Craig Kletzing - Waves in the Radiation Belts: Overview and Initial Results from the Van Allen Probes 5. Lynn Kistler - The Ionospheric Contribution to Magnetospheric Plasma Population 6. Xinlin Li: Results from Colorado Students Space Weather Experiment (CSSWE) (Special presentation) 7. John Lyon: Future Directions for Global Magnetospheric Modeling 8. Reiner Friedel - Wave-particle Interaction in the Inner Magnetosphere (Student-selected tutorial) We are grateful to the tutorial speakers for providing their presentation materials. If you use the content in any of these presentations, please do cite the original source. ---------------------------------------------------------------------- 2. 2013 Workshop Report from Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures Focus Group (FG) ---------------------------------------------------------------------- From: Hui Zhang, Q.-G. Zong, Michael Ruohoniemi, and David Murr The "Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures" focus group held four sessions with 25 presentations. The sessions were organized as follows: 1. Foreshock Phenomena 2. Ground Signatures 3. Magnetopause Phenomena (joint with Reconnection FG) 4. Planning session Session 1 - Monday, June 17, 3:30-5:00pm (Foreshock Phenomena) Various foreshock phenomena including hot flow anomaly (HFA), spontaneous hot flow anomalies (SHFAs), and foreshock bubbles (FBs) were investigated by this focus group using both in-situ observations and global hybrid simulations. Turner et al. gave an overview of foreshock bubbles and their effects on particle acceleration and the magnetosphere-ionosphere system. They showed the enhanced fluxes of energetic particles up to ~10 keV seen in FBs and attributed the enhanced fluxes as evidence for acceleration via Fermi and shock-drift acceleration processes. They also showed that FBs can excite global ULF waves with Pc 5 frequencies, which were observed by Cluster, THEMIS, and GOES located in the magnetosphere. Great progress has been made on SHFA studies since 2012 GEM, when Omidi et al. and Zhang et al. showed that HFAs can be generated spontaneously (in the absence of any current sheets) at quasi-parallel bow shocks through both in-situ observations and global hybrid simulations. Using global hybrid simulations, Omidi et al. demonstrated that SHFAs are generated at MA as low as 3, however, their rate of formation increases with MA. They also showed that SHFAs may form at all cone angles. Wang et al. (presented by Zhang) investigated more than 500 HFAs from Cluster-C1 observations from 2003 to 2009 and found that 58% of the HFAs are SHFAs and statistical study based on Cluster data shows that traditional HFAs have larger amplitude than SHFAs. Facsko et al. presented a case study of the magnetic turbulent properties inside a mature HFA observed by Cluster spacecraft. With high-pass filtering, they showed the existence of magnetic turbulence inside the HFA cavity, while the low frequency part of the turbulence might be hidden by wave activities. Zhang et al. investigated the ion and electron spectra inside HFAs and found that both ion and electron spectra can be used to classify young and mature HFAs. In addition, classifications according to ion and electron spectra are not absolutely consistent, which might be due to different heating mechanisms and efficiency for ions and electrons. They also found that the motional electric fields pointing towards the discontinuity on at least one side of the discontinuity is not a necessary condition to generate HFAs. Chu et al. showed that both mature and young HFAs are more prevalent when there is an approximately radial interplanetary magnetic field. Omidi et al. presented hybrid simulation results of interaction of CIR shocks with the bow shock. They showed that this interaction can: 1. Cause waves that propagate through the magnetosheath and the plasma depletion layer. 2. Modify magnetopause reconnection and compress the magnetosphere. 3. Energize ions including those accelerated through reconnection to higher energies and result in their trapping in the magnetosphere. 4. Generate/amplify electromagnetic waves in the magnetosphere. 5. Enhance ion precipitation into the ionosphere. Session 2 - Tuesday, June 18, 10:30-12:15pm (Ground Signatures) The foreshock phenomena may have significant impacts on the Earth’s Magnetosphere-Ionosphere System. Presentations in this session used a variety of space- and ground-based measurements to examine the response of the magnetosphere to solar wind transients and various foreshock phenomena. There were two talks on MI Coupling aspects. Michael Hartinger demonstrated that foreshock transients are effective drivers of the full range ULF waves; from single transient TCV/MIEs, stimulating field line resonances, and global modes as well. However, David Murr showed that not all foreshock transients cause ground signatures. This is not surprising but it means that we will now need to focus some effort on studying how different foreshock transients deform the magnetopause and which deformations are effective in driving field- aligned current systems in the MI system. There were three talks on Pc1-3 wave activity (Engebretson, Kim, and Bering) and the main conclusions can be summarized as follows. In addition to the field-aligned current system traditionally used to identify events from the ground, Pc1-3 wave bursts are an important observable for identifying and cataloging events (particularly near noon, where the FAC system is generally weak). Dayside transients including solar wind pressure pulses and foreshock transients can stimulate EMIC waves and modify the transmission of foreshock Pc3 waves to the ground. There were two talks on other observational techniques (Frey and Baker). Optical and radar observations have not yet been fully exploited to regularly characterize dayside transients (at least not in our FG activities to date). Session 3 - Tuesday, June 18, 1:30-3:00pm (Joint Transient Phenomena/Reconnection session) The broad topics of the joint Transient Phenomena/Reconnection session were (1) the production, evolution, and consequences of flux transfer events (FTEs), (2) plasma transport into the magnetosphere due to Kelvin-Helmholtz instabilities (KHI) and magnetic reconnection, and (3) the effect on reconnection rate and particle acceleration due to strong asymmetries such as those habitually at the polar cusps and transiently from plasmaspheric drainage plumes impacting the magnetopause. There were two presentations on observational aspects of FTEs. Karlheinz Trattner (Lockheed Martin) showed observational evidence for a hemisphere effect for FTEs. Yaireska Collado-Vega (GSFC) presented Cluster observations showing FTE motion is strongly dependent on conditions in interplanetary space. Some FTEs move with a sunward component; most of these events had a strong By, which is consistent with predictions from Sibeck and Lin. There were four presentations broadly on plasma transport through KHI and reconnection. Binzheng Zhang (Dartmouth) showed LFM simulations that included a non-zero By. He discussed the entry of electrons into the cusp due to dayside reconnection, and that there are two different populations. There was a discussion on the relative importance of reconnection and KHI. Takuma Nakamura (Los Alamos) showed results of 3D particle-in-cell simulations of secondary reconnection occurring during KHI, emphasizing the necessity of 3D. The reconnection can disturb the vortex and generate turbulence, which enhances mixing and transport. Xuanye Ma (University of Alaska) discussed the interaction of KHI and reconnection for large magnetic shear. In particular, each affect strongly impacts the other, with KHI limiting the reconnected flux and modifying the dissipation region structure. A guide field decreases the growth of KHI. Finally, Shiva Kavosi (University of New Hampshire) showed global magnetohydrodynamic simulations with Open GGCM of the KHI using parameters obtained from observations by THEMIS. She showed that results from Open GGCM simulations and THEMIS observations are consistent. She also showed that the frequency and amplitude of the KH waves depend on the solar wind driving velocity-larger driving velocities generating KH waves with higher frequencies and larger amplitude. There were two presentations on reconnection affected by asymmetries in the cusp and due to plasmaspheric plumes. Rick Wilder (CU-LASP) showed Cluster observations of reconnection at the polar cusp, which is strongly asymmetric and has a significant shear flow. He observed the exhaust is predominantly on the magnetospheric side of the magnetopause, consistent with theoretical predictions of asymmetric reconnection. He also compared the observed outflow speed to theoretical predictions. Sun-Hee Lee (University of Alaska) presented observations of cold ions in magnetopause reconnection, which likely come from plasmaspheric plumes. The particles accelerate near the flow boundary, being picked up by the electric field and have a mass dependent energization. These particles are not seen on the magnetosheath side, indicating that they may play a very limit role in the reconnection process. The results presented in this session are important for the role of reconnection in solar wind-magnetospheric coupling, magnetospheric convection, particle acceleration, and for plasma transport into the magnetosphere. Session 4 - Tuesday, June 18, 3:30-5:00pm (Planning Session) Three talks were presented in this session because they could not fit into other sessions due to limited time. Joe Borovsky presented the effect of sudden wind shears on the Earth’s magnetosphere predicted by MHD simulations, including boundary-layer motions, transient magnetosphere-ionosphere currents, transients in cross-polar-cap potential, and magnetotail disconnections. Andrey Samsonov presented THEMIS observations of sudden impulses in the magnetosphere. He showed that compressional waves can be observed very deep (~1.8 RE) in the magnetosphere and amplitude of these waves will decrease closer to the Earth. Xiaoyan Zhou presented the aurora signature of the magnetopause reconnection. The red aurora emissions indicated an equatorward expansion of the cusp due to the magnetopause erosion during the dayside magnetic reconnection. During the last 40 minutes of the planning session, we discussed post summer workshop plan. The focus group is working on a list of events that can be analyzed by the entire community from different perspectives. A table and a short description of some transient foreshock phenomena, together with a list of HFA and FB events observed by THEMIS in 2008 with summary plots has been posted on the GEM wiki page. We plan to extend the event list to include 2007 THEMIS events as well as Cluster events. We also plan to put other event list online, e.g., interplanetary shock list and TCV list. The focus group will also be joining the GSFC Monday Dayside science teleconference (supported by THEMIS) at noon as a mechanism for continued communication and presentation of science topics. +-------------------------------------------------------------------+ | 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 | +-------------------------------------------------------------------+