SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 7 - April 07, 2006

90 ASTROPHYSICS
Includes cosmology; celestial mechanics; space plasmas; and interstellar and interplanetary gases and dust.

20060009463 NASA Goddard Space Flight Center, Greenbelt, MD, USA

Using an MHD simulation to interpret the global context of a coronal mass ejection observed by two spacecraft

Riley, Pete; Linker, J. A.; Mikic, Z.; Odstrcil, D.; Zurbuchen, T. H.; Lario, D.; Lepping, R. P.; Journal of Geophysical Research; July 8, 2003; ISSN 0148-0227; Volume 108, No. A7; 11 pp.; In English; Original contains color illustrations; Copyright; Avail.: Other Sources

In late February 1999 the ACE spacecraft observed a coronal mass ejection (CME) at 1 AU, in the ecliptic plane. Thirteen days later, Ulysses observed a CME at 5 AU and 22's. We present a detailed analysis of the plasma, magnetic field, and composition signatures of these two events. On the basis of this comparison alone, it is not clear that the two spacecraft observed the same solar event. However, using a generic MHD simulation of a fast CME initiated at the Sun by magnetic flux cancellation and propagated out into the solar wind, together with additional evidence, we argue that indeed the same CME was observed by both spacecraft. Although force-free models appear to fit the observed events well, our simulation results suggest that the ejecta underwent significant distortion during its passage through the solar wind, indicating that care should be taken when interpreting the results of force-he models. Comparison of composition measurements at the two spacecraft suggests that significant spatial inhomogeneities can exist within a single CME. Author

Coronal Mass Ejection; Magnetohydrodynamics; Simulation; Space Plasmas; Magnetic Fields; Solar Wind; Interplanetary Gas; Plasma Composition; Plasma Interactions

Source: NASA