Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufmsh33a1188m&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #SH33A-1188
Astronomy and Astrophysics
Astronomy
7513 Coronal Mass Ejections, 7514 Energetic Particles (2114), 7839 Nonlinear Phenomena, 7843 Numerical Simulation Studies, 7851 Shock Waves
Scientific paper
Most high-energy solar energetic particles (SEPs) are believed to be accelerated at shock waves driven by coronal mass ejections (CMEs). The acceleration process strongly depends on the shock geometry, and the structure of the sheath that forms behind the shock. In an effort to understand the structure and time evolution of such CME-driven shocks and their relevance to particle acceleration, we investigate the interaction of a fast CME with the ambient solar wind by means of a three-dimensional (3-D) numerical ideal magnetohydrodynamics (MHD) model. Our global steady-state coronal model possesses high-latitude coronal holes and a helmet streamer structure with a current sheet near the equator, reminiscent of near solar minimum conditions. Fast and slow speed solar wind flow at high and low latitude respectively and the Archimedian spiral geometry of the interplanetary magnetic field is reproduced by solar rotation. Within this model system, we drive a CME to erupt by the introduction of a Gibson-Low magnetic flux rope that is embedded in the helmet streamer in an initial state of force imbalance. The flux rope rapidly expands and is ejected from the corona with maximum speeds in excess of 1000 km/s driving a fast-mode shock from the inner corona to a distance of 1 astronomical unit (AU). We find that the ambient solar wind structure strongly affects the evolution of the CME-driven shocks causing deviations of the of the fast-mode shocks from their expected global configuration. These deflections lead to substantial compressions of the plasma and magnetic field in their associated sheath region. The sudden post-shock increase in magnetic field strength on low latitude field lines is found to be effective for accelerating particles to the GeV range.
de Zeeuw D.
Gombosi Tamas
Igor S. V.
Kota József
Manchester Ward B.
No associations
LandOfFree
CME Shock and Sheath Structures Relevant to Particle Acceleration does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with CME Shock and Sheath Structures Relevant to Particle Acceleration, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and CME Shock and Sheath Structures Relevant to Particle Acceleration will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1462300