HR: 15:25h
AN: SH13B-08    [Abstracts]
TI: A Study of the Global Heliospheric Magnetic Flux Using In-Situ Data and the SAIC MHD Model
AU: * Lepri, S T
EM: slepri@umich.edu
AF: University of Michigan, Atmospheric, Oceanic, and Space Sciences 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Antiochos, S K
EM: antiochos@nrl.navy.mil
AF: E.O. Hulburt Center for Space Research, Naval Research Laboratory 4555 Overlook Dr., Washington, DC 20375 United States
AU: Riley, P
EM: pete.riley@saic.com
AF: SAIC, 10260 Campus Point Dr., San Diego, CA 92121 United States
AB: There has been considerable controversy in recent years over the slow evolution of the Sun's open field, which extends out to become the heliospheric magnetic field. In the standard solar model (e.g., Wang and Sheeley [1993]) the open flux can increase or decrease in response to the emergence or cancellation of magnetic flux at the photosphere in relation to coronal holes. In the Fisk et al. [1999a, 1999b] model, on the other hand, the open flux is conserved and evolves primarily via interchange reconnection with closed fields. This model predicts no long-term variations in the amount of heliospheric flux. We compare and test these theories by measuring the behavior of the open magnetic flux in the global heliospheric magnetic field. Using multi-point measurements from the VHM instrument on the Ulysses spacecraft and from the MAG instrument on the ACE spacecraft, we analyze in-situ radial magnetic field data and compare the behavior to that predicted by the updated SAIC MHD model. During solar maximum, ICMEs significantly disturb the heliospheric magnetic field, making our comparisons difficult. We examine the radial component of the magnetic field in data from 1991 though the present in order to determine the variability of the open flux and hence the evolution of corona holes.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7511 Coronal holes
DE: 7524 Magnetic fields
DE: 7537 Solar and stellar variability (1650)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005