SH42A-01 INVITED 

Secchi Observations of Mass Flows in the Inner Heliosphere

* Sheeley, N R (neil.sheeley@nrl.navy.mil), Naval Research Laboratory, Code 7672 4555 Overlook Ave. SW, Washington, DC 20375-5352, United States Herbst, A D (adh38@cornell.edu), Naval Research Laboratory, Code 7672 4555 Overlook Ave. SW, Washington, DC 20375-5352, United States Palatchi, C A (munchkin233@gmail.com), Naval Research Laboratory, Code 7672 4555 Overlook Ave. SW, Washington, DC 20375-5352, United States Wang, Y (ywang@yucca.nrl.navy.mil), Naval Research Laboratory, Code 7672 4555 Overlook Ave. SW, Washington, DC 20375-5352, United States

We use SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) observations to construct "height/time" maps of material flows in the heliosphere from the Sun to elongation angles beyond 90 degrees. Close to the Sun, we see accelerating tracks of ejecta (like streamer blobs) close to the sky plane. Farther from the Sun, we see groups of parallel tracks, some near the sky plane and some out of the plane. At the greatest elongations, we see a collection of non-parallel tracks, some merging and some crossing, and mainly from directions well out of the sky plane. These maps and their associated time- lapse movies are providing a new view of mass flows and their interactions in the inner heliosphere.

SH42A-02 

Stereo Triangulation of Solar Type III Radio Bursts

* Reiner, M J (michael.reiner@gsfc.nasa.gov), Catholic University and NASA/GSFC, Code 674, Greenbelt, MD 20771, United States Goetz, K (Goetz@umn.edu), University of Minnesota, School of Physics and Astronomy, Minneapolis, MN 20771, United States Fainberg, J (joseph.fainberg@nasa.gov), NASA Goddard Space Flight Center, Code 673, Greenbelt, MD 20771, United States Kaiser, M (Michael.Kaiser@nasa.gov), NASA Goddard Space Flight Center, Code 674, Greenbelt, MD 20771, United States Cecconi, B (baptiste.cecconi@obspm.fr), Observatoire de Paris, LESIA, Meudon, MD 92195, France Makisimovic, M (milan.maksimovic@obspm.fr), Observatoire de Paris, LESIA, Meudon, MD 92195, France Hoang, S (song.hoang@obspm.fr), Observatoire de Paris, LESIA, Meudon, MD 92195, France Bougeret, J (Jean-Louis.Bougeret@obspm.fr), Observatoire de Paris, LESIA, Meudon, MD 92195, France Bale, S D (BALE@sunspot.ssl.berkeley.edu), Univerity of California, Berkeley, Space Sciences Laboratory, Berkeley, CA 99999, United States

The radio receivers on the twin STEREO spacecraft provide the first dedicated remote stereoscopic observations of interplanetary radio sources of solar origin. These observations, from widely separated vantage points, enable the remote location and tracking of radio sources through the 3D heliosphere by two spacecraft triangulation. The direction of arrival of the radiation is deduced from the observed differences in the amplitudes and phases of the signals on the three mutually orthogonal antennas on each STEREO spacecraft, as well as from the observed timing differences due to the different light propagation times from the source to each spacecraft. These observations, together with simultaneous remote radio direction finding and timing measurements from the Wind and Ulysses spacecraft, provide an unprecedented self-consistent observation of solar radio sources in interplanetary space. Now with the angular separation between the STEREO spacecraft in excess of 20 degrees, we present preliminary results of the first 3 and 4 spacecraft triangulations for solar type III radio bursts that were simultaneously observed by STEREO A, STEREO B, Wind and Ulysses. This information is used to determine the intrinsic physical characteristics of these radio sources, such as the brightness temperatures and beaming characteristics, at different observing radio frequencies. For example, we find that for an eastern source, the relative amplitudes between STEREO A and B differ by a factor of two, indicative of significant beaming in the radio source region.

SH42A-03 

Multipoint Analysis by STEREO and WIND of the Magnetic Cloud on May 21-23, 2007

* Huttunen, K E (huttunen@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Luhmann, J G (jgluhman@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Li, Y (yanli@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Lynch, B (blynch@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Liu, Y (liuxying@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Schroeder, P (peters@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Bale, S D (bale@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Lee, C O (clee@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Lin, R P (rlin@ssl.berkeley.edu), Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, Berkeley, CA 94720, United States Vourlidas, A (vourlidas@nrl.navy.mil), Solar Physics Branch, Naval Research Laboratory, Washington, DC 20375, United States Farrugia, C (charlie.farrugia@unh.edu), Space Science Center, University of New Hampshire, Durham, NH103824, United States Galvin, A B), Space Science Center, University of New Hampshire, Durham, NH103824, United States Acuna, M H (mario.acuna@nasa.gov), NASA/Goddard Space Flight Center, Code 674, Greenbelt, MD 20771, United States Howard, R A (russ.howard@nrl.navy.mil), Solar Physics Branch, Naval Research Laboratory, Washington, DC 20375, United States Kaiser, M (Kaiser michael.kaiser@nasa.gov), NASA/Goddard Space Flight Center, Code 674, Greenbelt, MD 20771, United States Mewaldt, R A (rmewaldt@srl.caltech.edu), Space Radiation Laboratory, Caltech, 220-47 Downs Lab, Pasadena, CA 91125, United States Sauvaud, J (sauvaud@cesr.fr), CESR/CNRS, 9 av Colonel Roche, Toulouse, 31028, France Wiedenbeck, M (Mark.E.Wiedenbeck@jpl.nasa.gov), Jet Propulsion Laboratory, MS 169-327, Pasadena, CA 91109, United States

We will present multi-spacecraft observations by STEREO A and B and WIND of a magnetic cloud in the interplanetary space on May 21-23, 2007. At that time the angular separation between STEREO A and B was nearly 10 degrees. The differences in the observed magnetic field signatures at the locations of the spacecrafts suggest that they crossed the different parts of the magnetic cloud. STEREO B observed a very clear rotation of the magnetic field direction and presumably crossed the cloud close to the center whereas STEREO A likely traversed the leg of the magnetic cloud. Although the magnetic field maximum within this cloud was ~17 nT it did not produce significant geomagnetic response since the Z-component of the magnetic field was orientated northward. We will analyze the structure of the magnetic cloud at each spacecraft in order to deduce its larger-scale structure and orientation. In addition, we will study the solar source region of the magnetic cloud as well as the coronagraph and radio wave observations.

SH42A-04 

Heliospheric Streamers: Comparison Between Model Calculations and SECCHI Observations

* Howard, R A (russell.howard@nrl.navy.mil), Naval Research Laboratory, Code 7660 4555 Overlook Ave, SW, Washington, DC 20375, United States Thernisien, A (arnaud.thernisien@nrl.navy.mil), Universities Space Research Association, 10211 Wincopin Circle, Suite 620, Columbia, MD 21044, United States Vourlidas, A (angelos.vourlidas@nrl.navy.mil), Naval Research Laboratory, Code 7660 4555 Overlook Ave, SW, Washington, DC 20375, United States Morrill, J S (jeff.morrill@nrl.navy.mil), Naval Research Laboratory, Code 7660 4555 Overlook Ave, SW, Washington, DC 20375, United States MacNiece, P (pmacneice@pop900.gsfc.nasa.gov), NASA/GSFC, Code 674, Greenbelt, MD 20771, United States

We have generated a time dependent 3-dimensional description of the electron density distribution out to 1 AU using the ENLIL model at the Community Coordinated Modeling Center (CCMC). Using this electron density description we have computed the brightness measurements that would be observed by coronagraphic instruments such as SECCHI using the Raytrace package. We compare the computed images with the actual SECCHI observations of streamers/heliospheric current sheet.

SH42A-05 

Imaging Coronal Mass Ejections in the Heliosphere using the STEREO Heliospheric Imagers

* Harrison, R A (r.harrison@rl.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Davis, C J (c.j.davis@rl.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Eyles, C J (cje@star.bham.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Eyles, C J (cje@star.bham.ac.uk), School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, United Kingdom Bewsher, D (d.bewsher@rl.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Crothers, S (s.crothers@rl.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Davies, J A (j.a.davies@rl.ac.uk), Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom Howard, R A (russ.howard@nrl.navy.mil), Space Science Division, Naval Research Laboratory, Washington DC, 20375, United States Moses, D J (moses@nrl.navy.mil), Space Science Division, Naval Research Laboratory, Washington DC, 20375, United States Halain, J (jphalain@ulg.ac.be), Centre Spatial de Liege, Universtte de Liege, ave Pre Aily, Liege, B-4031, Belgium

We present images of Coronal Mass Ejections in the heliosphere, tracked from the outer corona to Earth-like distances, from the first months of the scientific operation of the Heliospheric Imagers (HI) aboard the NASA STEREO spacecraft. The HI instruments are wide-angle imaging systems designed to detect CMEs in the heliosphere, in particular, for the first time, observing the propagation of such events along the Sun-Earth line. These early results show that despite severe technical challenges in their design and implementation, the HI instruments can successfully detect CMEs in the heliosphere and this is an extremely important milestone for CME research. Among the early results, we show a number of CME events, demonstrating the ability to extract the F-coronal intensity distribution, and to track a CME from the corona to the Earth. Early investigations of the velocity profiles of CMEs as they propagate through the heliosphere and of their basic structure will be presented.

SH42A-06 

Propagation Characteristics of the 2007 August 21 Coronal Mass Ejection as Determined by Geometric Localization

* de Koning, C A (curt.a.dekoning@noaa.gov), University of Colorado at Boulder, CIRES-SEC Mail Code W/NP9 325 Broadway, Boulder, CO 80305, United States Pizzo, V J (Vic.Pizzo@noaa.gov), NOAA Space Environment Center, Mail Code W/NP9 325 Broadway, Boulder, CO 80305, United States Biesecker, D A (Doug.Biesecker@noaa.gov), NOAA Space Environment Center, Mail Code W/NP9 325 Broadway, Boulder, CO 80305, United States

The geometric localization technique [Pizzo and Biesecker, 2004] utilizes a series of lines of sight from two space-based observatories in order to determine gross propagation characteristics of coronal mass ejections (CMEs). We have set up this tool to work specifically with STEREO (Solar TErrestrial RElations Observatory) coronagraph observations. Here, we employ this technique to the CME of 21 August 2007 and present results on the speed and direction of propagation for this CME. This technique meets a need within the space weather community for a means to accurately determine the gross properties of Earth-directed CMEs from a near-real- time data stream, such as the one provided by the STEREO Space Weather Beacon.

SH42A-07 

3D Reconstruction of the Electron Density in the Corona from COR1 STEREO Observations

* Kramar, M (kramar@helio.gsfc.nasa.gov), The Catholic University of America, NASA-GSFC, Code 671, Greenbelt, MD 20771, United States * Kramar, M (kramar@helio.gsfc.nasa.gov), NASA-GSFC, Code 671, Greenbelt, MD 20771, United States Jones, S (shaelatoo@yahoo.com), NASA-GSFC, Code 671, Greenbelt, MD 20771, United States Jones, S (shaelatoo@yahoo.com), University of Maryland, Department of Physics, College Park, MD 20742, United States Davila, J (Joseph.M.Davila@nasa.gov), NASA-GSFC, Code 671, Greenbelt, MD 20771, United States Inhester, B (inhester@mps.mpg.de), Max-Planck Institut fuer Sonnensystemforschung, Max-Plank-Str. 2, Katlenburg-Lindau, 37191, Germany

We present 3D reconstruction for the electron density in the corona based on the COR1 STEREO observations. The reconstruction is performed by using regularized tomography inversion method. Since the solar corona is optically thin, coronal observations are essentially integrated over the line-of-sight (LOS). It is therefore impossible to resolve the structure of the corona along the LOS if observations are provided from a single view direction. Observations from different view positions are necessary to reconstruct 3D coronal structure and is the essence of the tomography inversion method. When having observations only from a single view direction, a rigid rotation of the coronal density structures with the Sun about the ecliptic must be assumed in order to apply the tomography technique. As a consequence, only structures which are stationary over half a solar rotation can be reconstructed. The STEREO observations allow us to reduce this stationarity assumption. For reconstruction we choose a period when the Sun is relatively quite. However some active events occurred, and we need to skip the data for these events. Therefore, in order to stabilize the reconstruction, the smoothness factor was used as regularization constraint during the inversion.

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