SM21C-01 INVITED 

Recent Cluster Results on Cusp and Magnetopause Boundary Phenomena

* Dunlop, M W (m.dunlop@rl.ac.uk), RAL, SSTD, RAL, Chilton, DIDCOT, OXON, OX11 0QX, United Kingdom * Dunlop, M W (m.dunlop@rl.ac.uk), Imperial College London, The Blackett Laboratory, Imperial College London, London, SW7 2AZ, United Kingdom Bogdanova, Y (jb@mssl.ucl.ac.uk), University College London, Mullard Space Science Laboratory, University College London, Dorking, Surrey, RH5 6NT, United Kingdom Escoubet, p (Philippe.Escoubet@esa.int), ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200 AG, Netherlands Fazakerley, A N (anf@mssl.ucl.ac.uk), University College London, Mullard Space Science Laboratory, University College London, Dorking, Surrey, RH5 6NT, United Kingdom Lavraud, B (lavraud@lanl.gov), LANL, Space and Atmospheric Science, Los Alamos National Laboratory, Los Alamos, NM 87545, United States Taylor, M G (mtaylor@rssd.esa.int), ESA/ESTEC, Keplerlaan 1, Noordwijk, 2200 AG, Netherlands Pitout, F (Frederic.Pitout@obs.ujf-grenoble.fr), CNRS/UJF, Laboratoire de Planétologie de Grenoble, CNRS/UJF, Bâtiment D de Physique, BP 53, Cedex 9, Grenoble, 38041, France Pu, Z (zypu@pku.edu.cn), Peking University, School of Earth and Space Sciences, Peking University, Beijing, 100871, China Shen, C (sc@center.cssar.ac.cn), CSSAR, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, 100080, China

The combined data sets of Cluster and Double Star have provided extensive, multi-scale coverage of the Earth's magnetosphere. Since 2001 the Cluster orbit has preferentially sampled the high and mid altitude cusp regions during the spring seasons, and crossed both the high and low latitude, dayside magnetopause at other times. We present an overview of the most recent Cluster research on both the dayside and boundary layer phenomena based predominantly on multipoint studies. The Doublestar TC-1 spacecraft has also sampled either the subsolar region of the magnetopause, or southerly latitudes, at similar local times to cluster. We therefore also review coordinated CLUSTER-Double Star conjunctions for a number of dayside passes to investigate reconnection associated signatures observed at different locations. We Focus on both transient FTEs, arising from opened flux ropes during intermittant reconnection, and comparative boundary layer signatures during cusp and magnetopause transitions and investigate structure and dynamics of the magnetopause and FTE occurance on motion. Cluster provides good coordination with ionospheric instrumentation, particularly the EISCAT and SuperDARN radars and ground magnetomters and we also review investigations of the ground signatures of reconnection (FTEs and boundary layers) and other features of magnetospheric response. The spacecraft are conjugate simulataneously with both the ESR radar on Svalbard, and the Antarctic station at Zhongshan, when the ground stations lie under the cusp position, Cluster is passing out from the northern cusp and TC-1 is near the magnetopause.

SM21C-02 

Cluster and Ground-Based Observations of Flux Transfer Events During the 10,000 km Separation Season

* Fear, R C (r.fear@ion.le.ac.uk), University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom Milan, S E (steve.milan@ion.le.ac.uk), University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom Fazakerley, A N (anf@mssl.ucl.ac.uk), Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, United Kingdom Lucek, E A (e.lucek@imperial.ac.uk), Imperial College London, Prince Consort Road, London, SW7 2BZ, United Kingdom

Between 1920 and 1950~UT on 27th January 2006, the Cluster spacecraft straddled the dayside magnetopause slightly equatorward of the cusp in the post-noon sector. The spacecraft formed a tetrahedron with a scale length of 10,000~km. The lagged IMF was largely directed sunward, but with weak and approximately equal duskward and southward components. A series of flux transfer events (FTEs) were observed by differing subsets of the Cluster spacecraft, three of which were observed by all four spacecraft. Multi-spacecraft timing analysis indicates that these FTEs moved predominantly latitudinally, but their observation at all four spacecraft indicates that these three FTEs extend longitudinally for at least 10,000~km. Simultaneously, pulsed ionospheric flows (PIFs) were observed, although there is no clear one-to-one correlation between the PIFs and the FTEs. We present in situ observations, along with attempts to quantify the flux reconnected during this interval using ground-based observations.

SM21C-03 

Structure and Dynamics of the Inner Boundary of the Plasma Sheet: THEMIS Observations

* Runov, A (andrei.runov@oeaw.ac.at), Institute of Geophysics and Planetary Physics, University of California, Los Angeles, 3845 Slichter Hall, Los Angeles, CA CA 90095-1, United States * Runov, A (andrei.runov@oeaw.ac.at), Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, A- 8042, Austria Angelopoulos, V (vassilis@ucla.edu), Institute of Geophysics and Planetary Physics, University of California, Los Angeles, 3845 Slichter Hall, Los Angeles, CA CA 90095-1, United States Baumjohann, W (baumjohann@oeaw.ac.at), Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, A- 8042, Austria Nakamura, R), Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, A- 8042, Austria Sergeev, V), St. Petersburg State University, Petrodvoretz, St. Petersburg, 198504, Russian Federation Larson, D (davin@ssl.berkeley.edu), Space Science Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA CA 94720-7, United States McFadden, J (mcfadden@ssl.berkeley.edu), Space Science Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA CA 94720-7, United States Glassmeier, K (kh.glassmeiertu-bs.de), Institute for Geophysics and Extraterrestrial Physics, TU Braunschweig, Mendelsonstrasse 3, Braunschweig, D-38106, Germany Auster, H (uli.austertu-bs.de), Institute for Geophysics and Extraterrestrial Physics, TU Braunschweig, Mendelsonstrasse 3, Braunschweig, D-38106, Germany

During its coast phase from mid of March until end of April 2007, the THEMIS spacecraft monitor the pre-midnight region of the near-Earth plasma sheet, crossing its inner edge near the geomagnetic equator. The pearls-on- string configuration of the THEMIS constellation enables to study motion of the inner boundary of the plasma sheet and plasma sheet particle injections into the inner magnetosphere during variations of geomagnetic activity. In this paper, we present profiles of particle energy fluxes along the spacecraft trajectory (nearly radial) obtained by the ESA and SST instruments during substorms. Using the small separations (0.3 - 0.5 R_E) of the three middle probes and the spin-resolution (3 s) of the particle flux data, we study the motion of the particle injection fronts associated with magnetic field variations with time scales from several to several tens of minutes.

SM21C-04 

First THEMIS Results Concerning the Nature and the Role of the Electromagnetic Waves During Substorm Process Versus Radial Distance

* Le Contel, O (olivier.lecontel@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Roux, A (alain.roux@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Robert, P (patrick.robert@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Coillot, C (cco@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Bouabdellah, A (abe@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Alison, D (dal@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Rucco, S (sebastien.ruocco@cetp.ipsl.fr), CETP/CNRS/UVSQ/UPMC, 10-12,avenue de l'Europe, VELIZY, F-78140, France Chaston, C C (ccc@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Angelopoulos, V (vassilis@ssl.berkeley.edu ), SSL, University of California, Berkeley, CA 94720, United States Bonnell, J W (jbonnell@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Larson, D (davin@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Mc Fadden, J (mcfadden@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Carlson, C W (cwc@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Mende, S B (mende@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Frey, H (hfrey@ssl.berkeley.edu), SSL, University of California, Berkeley, CA 94720, United States Ergun, R (Ree@Fast. Colorado. Edu ), LASP, University of Colorado, Boulder, CO 80303-7814, United States Cully, C M (cully@colorado.edu), LASP, University of Colorado, Boulder, CO 80303-7814, United States Glassmeier, K (kh.glassmeier@t-online.de), TUBS, Mendelssohnstr. 3, 4. OG., Zi. 401, Braunschweig, 38106, Germany Auster, U (uli.auster@tu-bs.de), TUBS, Mendelssohnstr. 3, 4. OG., Zi. 401, Braunschweig, 38106, Germany Russell, C T (ctrussel@igpp.ucla.edu), IGPP, University of California, Los Angeles, CA 90024, United States Donovan, E (donovan@phys.ucalgary.ca), Dept. of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, Canada Mann, I R), Dept. of Physics, University of Alberta, Edmonton, T6G 2G7, Canada

Current driven instabilities are thought to be the cause of electromagnetic waves with frequency around the proton gyrofrequency in the near-earth plasma sheet. It was suggested that they could be the substorm trigger. Lower hydrid drift instability in the near and mid magnetotail was invoked to provide the anomalous resistivity needed in order that resistive instabilities allow magnetic reconnection to develop in an otherwise collisionless regime. At smaller scale and higher frequencies, whistler mode waves are also expected to act as a dissipation mechanism in the electron diffusion region and/or are considered as signature of fast magnetic reconnection processes. Thus the nature and the role played by electromagnetic waves in the substorm process is still a matter of debate. Taking benefits of the radial distribution of the five THEMIS probes and of the comprehensive set of THEMIS instruments we present the first THEMIS analysis of electromagnetic wave activity during substorms as a function of the radial distance.

SM21C-05 

Highly periodic activations observed by THEMIS prior to substorm onset

* Kepko, L (larry.kepko@unh.edu), Space Science Center, University of New Hampshire Morse Hall 39 College Road, Durham, NH 03824, United States Raeder, J (j.raeder@unh.edu), Space Science Center, University of New Hampshire Morse Hall 39 College Road, Durham, NH 03824, United States Angelopoulos, V (vassilis@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Carlson, C (cwc@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Frey, H (hfrey@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Larson, D (davin@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States McFadden, J (mcfadden@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Mende, S (mende@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Parks, G (parks@ssl.berkeley.edu), Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, United States Glassmeier, K (kh.glassmeier@tu-bs.de), Institute of Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, Braunschweig, MA 38106, Germany Auster, U (uli.auster@tu-bs.de), Institute of Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, Braunschweig, MA 38106, Germany Donovan, E (eric@phys.ucalgary.edu), University of Calgary, SB 605 University of Calgary 2500 University Drive NW, Calgary, AB T2N1N4, Canada Russell, C (ctrussell@igpp.ucla.edu), Institute of Geophysics and Planetary physics, University of California, Los Angeles, Los Angeles, CA 90095, United States Ge, Y (ysge@igpp.ucla.edu), Institute of Geophysics and Planetary physics, University of California, Los Angeles, Los Angeles, CA 90095, United States Mann, I (imann@phys.ualberta.ca), Department of Physics, University of Alberta 11322-89 Avenue, Edmonton, AB T6G 2G7, Canada Henderson, M (mghenderson@lanl.gov), Los Alamos National Laboratory, Space Science and Applications Group ISR-1, Los Alamos, NM 87545, United States Yumoto, K (yumoto@serc.kyushu-u.ac.jp), Space Environment Research Center, Kyushu University, Hakozaki, Fukuoka, MA 812- 8581, Japan Singer, H (howard.singer@noaa.gov), NOAA Space Environment Center, 325 Broadway, Boulder, CO 80305, United States

On March 24, 2007, the THEMIS spacecraft observed near the dusk flank several 10 minute quasi-periodic flow and magnetic field oscillations followed by the onset of a strong substorm. The IMF was strongly southward during the event, although the start of the oscillations appeared to be associated with a brief but significant northward turning. Each of the oscillations was accompanied by an auroral intensification, an energetic particle injection, and ground Pi2 pulsations. We first characterize the timing of the events observed by the 5 THEMIS spacecraft, ground imagers and magnetometers, and geosynchronous spacecraft. We then examine whether the quasi-periodic activations were manifestations of an instability that lead to the onset of a global substorm.

SM21C-06 

Midlatitude Pi2 Timing of a Multiple Onset Substorm Observed by THEMIS on March 23, 2007

* McPherron, R L (rmcpherron@igpp.ucla.edu), Institute of Geophysics and Planetary Physics, Univ. of Calif Los Angeles, Los Angeles, CA 90095, United States Angelopolous, V (vassilis@ssl.berkeley.edu), Institute of Geophysics and Planetary Physics, Univ. of Calif Los Angeles, Los Angeles, CA 90095, United States Zhou, S (sha@atmos.ucla.edu), Dept. Ocean & Atmos. Sci., Univ. of Calif Los Angeles, Los Angeles, CA 90095, United States Yumoto, K (yumoto@geo.kyushu-u.ac.jp), Space Env Res Ctr, Kyushu Univ Graduate School of Sciences Space Env Res Ctr, Kyushu Univ Graduate School of Sciences, 6-10-1 Hakozaki Higashiku, Fukuoka, 812-8581, Japan Shiokawa, K (shiokawa@stelab.nagoya-u.ac.jp), Solar-Terrestrial Environment Lab, Nagoya University, 3-13, Honohara, Toyokawa, Aichi, Toyokawa, 442-8507, Japan Singer, H (howard.singer@noaa.gov), Space Enviornment Center, NOAA Broadway, Boulder, CO 80303, United States Rae, J (jrae@phys.ualberta.ca), Dept. of Physics, Univ. of Alberta, Edmonton, Alb T6G2G7, Canada

It is generally accepted that Pi 2 pulsations are associated with the onset of a magnetospheric substorm expansion phase. However, many substorms include more than one Pi 2 burst and it is sometimes difficult to determine which burst corresponds to the expansion onset rather than a pseudo breakup or poleward boundary intensification so that additional information is needed to make a positive identification of onset. In addition there are other concerns including the strength of the Pi 2 relative to background noise, different types of Pi 2, the polarization of the Pi 2 signal, and time delays that are functions of location relative to the onset meridian. In this paper we utilize data from several arrays of ULF wave detectors including the Themis ground stations in North America and the Circum Pacific Array to determine how these factors effect the accuracy of the onset determination. Additional information is provided by the Intermagnet ground magnetometers, Themis all sky cameras and GOES and LANL spacecraft at synchronous orbit. The time-line provided by the Pi2 analysis provides a framework with which the observations at the Themis spacecraft can be interpreted.

SM21C-07 

PENGUIn Observations of the THEMIS March 23, 2007 Substorm Event

* Lessard, M (marc.lessard@unh.edu), University of New Hampshire, Space Science Center Morse Hall, Durham, NH 03824, United States Weatherwax, A T (weatherwax@siena.edu), Siena College, Department of Physics, 515 Loudon Road, Loudonville, NY 12211, United States Clauer, R (rclauer@umich.edu), Virginia Tech, Department of Electric and Computer Engineering, Blacksburg, VA 24061, United States Engebretson, M J (engebret@augsburg.edu), Augsburg College, 2211 Riverside Ave, Minneapolis, MN 55454, United States Frey, H (hfrey@ssl.berkeley.edu), New Jersey Institute of Technology, Center for Solar-Terrestrial Research, Newark, NJ 07102, United States Inan, U (inan@stanford.edu), Stanford University, STAR Lab, 350 Serra Mall, Stanford, CA 94305-9515, United States LaBelle, J (jlabelle@aristotle.dartmouth.edu), Dartmouth College, Department of Physics and Astronomy, Hanover, NH 03755, United States Lanzerotti, L (ljl@njit.edu), University of California, Space Science Laboratory, Berkeley, CA 94720, United States Mende, S (mende@ssl.berkeley.edu), University of California, Space Science Laboratory, Berkeley, CA 94720, United States Petit, N (petit@augsburg.edu]), Augsburg College, 2211 Riverside Ave, Minneapolis, MN 55454, United States Ridley, A (ridley@umich.edu), University of Michigan, Space Physics Research Laboratory, Ann Arbor, MI 48109, United States Rosenberg, T (tjrosen@umd.edu), University of Maryland, Institute for Physical Science and Technology, College Park, MD 20742, United States Spasojevic, M), Stanford University, STAR Lab, 350 Serra Mall, Stanford, CA 94305-9515, United States Detrick, D (detrick@umd.edu), University of Maryland, Institute for Physical Science and Technology, College Park, MD 20742, United States

On March 23, 2007, the THEMIS array of satellites acquired data during an intense substorm, with the AE index reaching several hundred nT. In space over the Antarctic, THEMIS provided spatial information regarding the expected signatures, including dipolarization, fast flows and energetic particle injections. On the ground in the Antarctic, PENGUIn real-time observations from manned stations as well as from the Automated Geophysical Observatories (AGOs) show the high latitude perspective from the southern hemisphere. Magnetometer and induction coil data from the South Pole and from the P1 AGO site show that substorm activity began at least a couple hours earlier than that expressed by the AE index. VLF signals are observed only during the most intense period of the geomagnetic activity and Pi1B substorm signatures were recorded at various locations in both hemispheres, including at Poker Flat in Alaska. In this presentation, a contextual description of the substorm activity is presented, together with an extended discussion of ULF waves, showing the numerous aspects of the temporal evolution of the substorm. http://www.antarcticspacescience.org

SM21C-08 

OpenGGCM Simulation of the March 23, 2007 Substorm Observed by THEMIS

* Raeder, J (J.Raeder@unh.edu), Space Science Center, University of New Hampshire, 39 College Road, Durham, NH 03824, United States Kepko, L (Larry.Kepko@unh.edu), Space Science Center, University of New Hampshire, 39 College Road, Durham, NH 03824, United States Kaghashvili, E (Edisher.Kaghashvili@unh.edu), Space Science Center, University of New Hampshire, 39 College Road, Durham, NH 03824, United States Angelopoulos, V (Vassilis@ssl.berkeley.edu), IGPP, UCLA, Los Angeles, CA 90095-1567, United States Larson, D (Davin@ssl.berkeley.edu), Space Sciences Lab, University of California, 7 Gauss Way, Berkeley, CA 94270, United States McFadden, J (mcfadden@ssl.berkeley.edu), Space Sciences Lab, University of California, 7 Gauss Way, Berkeley, CA 94270, United States Carlson, C (cwc@apollo.ssl.berkeley.edu), Space Sciences Lab, University of California, 7 Gauss Way, Berkeley, CA 94270, United States Glassmeier, K (kh.glassmeier@tu-bs.edu), IGEP, TU Braunschweig, Mendelssohnstr. 3, Braunschweig, 38106, Germany Auster, U (uli.auster@tu-bs.edu), IGEP, TU Braunschweig, Mendelssohnstr. 3, Braunschweig, 38106, Germany Parks, G (parks@ssl.berkeley.edu), Space Sciences Lab, University of California, 7 Gauss Way, Berkeley, CA 94270, United States

On March 23, 2007 the 5 THEMIS spacecraft observed the onset of a substorm while located in the dusk flank of the magnetoshere. The substorm was also observed in ground-based data and in Polar UVI images. Using Wind data to drive the OpenGGCM we conducted a simulation study of this substorm. The simulation clearly shows the substorm characteristics, such as the current wedge and expansion of the aurora. In this paper we compare the OpenGGCM simulation with observations, address the magnetic mapping between THEMIS and the auroral features, and investigate whether this substorm was triggered by a sharp northward turn of the IMF.

Author(s) (2007), Title, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract #####-##.