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Ann. Geophys., 21, 1347-1357, 2003
www.ann-geophys.net/21/1347/2003/
© European Geosciences Union 2003
Dynamical evolution of the inner heliosphere approaching solar activity maximum: interpreting Ulysses observations using a global MHD model
P. Riley, Z. Mikić, and J. A. Linker
Science Applications International Corporation, 10260 Campus Point Dr., San Diego, CA 92121, USA
Abstract. In this study we describe
a series of MHD simulations covering the time period from 12 January 1999 to 19
September 2001 (Carrington Rotation 1945 to 1980). This interval coincided
with: (1) the Sun’s approach toward solar maximum; and (2) Ulysses’ second
descent to the southern polar regions, rapid latitude scan, and arrival into
the northern polar regions. We focus on the evolution of several key parameters
during this time, including the photospheric magnetic field, the computed
coronal hole boundaries, the computed velocity profile near the Sun, and the
plasma and magnetic field parameters at the location of Ulysses. The model
results provide a global context for interpreting the often complex in situ
measurements. We also present a heuristic explanation of stream dynamics to
describe the morphology of interaction regions at solar maximum and contrast it
with the picture that resulted from Ulysses’ first orbit, which occurred
during more quiescent solar conditions. The simulation results described here
are available at: http://sun.saic.com.
Key words. Interplanetary physics
(Interplanetary magnetic fields; solar wind plasma; sources of the solar wind)
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