CME-Magnetosphere Comparisons: Examples of IHY Universal Processes I: Posters

SPA-Solar and Heliospheric Physics [SH]

SH41B ACC:Chichen-Itza Hall Thursday

Presiding: M B Moldwin, Univ. of California, Los Angeles

SH41B-01

Modeling of the halo CME propagation using ENLIL Heliospheric Cone Model

* Taktakishvili, A (staktak@helio.gsfc.nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States
MacNeice, P (macneice@nccs.gsfc.nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States
Hesse, M (michael.hesse@nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States
Odstrcil, D (Dusan.Odstrcil@Colorado.edu), University of Colorado at Boulder, 216 UCB, Boulder, CO 80309, United States
Kuznetsova, M M (Maria.M.Kuznetsova@gsfc.nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States
Rastaetter, L (Lutz.Rastaetter.1@gsfc.nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States
Chulaki, A (achulaki@pop600.gsfc.nasa.gov), Community Coordinated Modeling Center, NASA/GSFC Code 674, Greenbelt, MD 20771, United States

We will test the ability of the ENLIL heliospheric cone model, available at the Community Coordinated Modeling Center (CCMC) of the NASA/GSFC, to model the propagation of halo CMEs. We will use different approaches to derive CME parameters from the LASCO/C3 instrument images. We also will study the sensitivity of the model performance to parameters that can not be derived from the observations. We will simulate a number of geomagnetic storms and series of events selected by community campaigns, including the recent fall AGU storm on December 15, 2006, to study ENLIL cone model performance comparing it to the ACE satellite data. The development of such a tool at the CCMC will support the development of space weather event forecasting.

SH41B-02

Accretion not Diversion One way ICME-sheaths differ from planetary magnetosheaths

* Siscoe, G L (siscoe@bu.edu), Boston University, Center for Space Physics 725 Commonwealth Ave, Boston, MA 02215, United States
Owens, M J (mjowens@bu.edu), Boston University, Center for Space Physics 725 Commonwealth Ave, Boston, MA 02215, United States
Hughes, W J (hughes@bu.edu), Boston University, Center for Space Physics 725 Commonwealth Ave, Boston, MA 02215, United States
Isenberg, P A (phil.isenberg@unh.edu), University of New Hampshire, Institute for the Study of Earth, Oceans, and Space, Durham, NH 03824, United States
Odstrcil, D (Dusan.Odstrcil@noaa.gov), Space Environment Center, 325 Broadway, Boulder, CO 80305, United States

ICME-sheaths differ from planetary magnetosheaths in that in a planetary magnetosheath, the solar wind flows around the planet, whereas in an ICME-sheath it piles up with little flow-around. We refer to the two types of sheaths as accretion type (ICME) and diversion type (planetary). That planetary magnetosheaths are of the diversion type is well known, but that ICME-sheaths are largely (though not totally) of the accretion type is newly recognized. We verify the statement using MHD simulations of solar wind flows in Earth's magnetosheath and in an ICME-sheath showing that the flow-around speed in the magnetosheath is about twice that in the ICME sheath. The simulations also show that the standoff distance between the shock and the body, normalized to radius of curvature, is also about twice as large in the magnetosheath as in the ICME-sheath. This result is confirmed by an analytical model. The two results - smaller flow-around speed and smaller flow-through distance in the ICME-sheath - imply that the solar wind mostly piles up in front of the ICME instead of flowing around it as it moves outward.

SH41B-03

Identifying and Characterizing Small-Scale Flux Rope Structures in the Solar Wind Over a Full Solar Cycle

* Cartwright, M L (mcartwri@ucla.edu), University of California, Los Angeles, 595 Charles E. Young Drive East Box 951567, Los Angeles, CA 90095, United States
* Cartwright, M L (mcartwri@ucla.edu), Institute of Geophysics & Planetary Physics, University of California, Los Angeles, Slichter 6869, Los Angeles, CA 90095, United States
Moldwin, M B (mmoldwin@igpp.ucla.edu), University of California, Los Angeles, 595 Charles E. Young Drive East Box 951567, Los Angeles, CA 90095, United States
Moldwin, M B (mmoldwin@igpp.ucla.edu), Institute of Geophysics & Planetary Physics, University of California, Los Angeles, Slichter 6869, Los Angeles, CA 90095, United States

A new class of flux ropes have been discovered with much smaller time (on the order of 1 hr) and length scales compared to day-long magnetic clouds. We developed an automated technique that identifies small-scale flux ropes through recognizing strong core fields coincident with bipolar signatures. Using our automatic technique we have analyzed WIND spacecraft magnetic field and plasma data from 1995-2005. We identified 213 flux ropes with a time-scale of 40 minutes up to 12 hours. The distribution of flux ropes per year peaks in1996 near solar minimum. The majority of flux ropes had a time-scale of 1 hour in length. Their solar wind context (i.e. relationship to the heliospheric current sheet, CIR's) and plasma properties (i.e. number density, proton temperature, etc.) are presented.

SH41B-04

Morphological Study of Coronal Mass Ejections using Wavelet

* Gonzalez-Gomez, D (isabeldgg@hotmail.com), Universidad Nacional Autonoma de Mexico, IGEF, Instituto de Geofisica, CU Coyoacan, Mexico, DF 04510, Mexico
Blanco-Cano, X (xbc@geofisica.unam.mx), Universidad Nacional Autonoma de Mexico, IGEF, Instituto de Geofisica, CU Coyoacan, Mexico, DF 04510, Mexico
Raga, A C (raga@nucleares.unam.mx), Universidad Nacional Autonoma de Mexico, ICN, Instituto de Ciencias Nucleares, CU, Coyoacan, Mexico, DF 04510, Mexico

The principal objective of this study is to analyze structures inside Coronal Mass Ejections (CMEs) using wavelet technique. We have used the archived public data taken with the SOHO/LASCO coronographs C2 and C3. We have found that different structures that can exist in a CME can be observed at different spatial scales of wavelets. We also look for the direction and orientation of the most intense flux that is present in a CME in the entire image. We intend to use the same wavelet technique to reconstruct the original image and obtain higher contrasts of the image.