HR: 1400h
AN: SH23C-03    [Abstracts]
TI: Balancing the Global Heliospheric Flux Budget
AU: * Lepri, S T
EM: slepri@umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109, United States
AU: Zurbuchen, T H
EM: thomasz@umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109, United States
AB: Interplanetary coronal mass ejections (ICMEs) have long been identified in situ by the presence of counterstreaming suprathermal electrons (CSEs) observed in situ. The presence of CSEs has been interpreted as indicating that the field lines along which they stream remain connected to the Sun as far away as 5 AU. In recent years, studies have shown that the degree of openness of ICMEs does not change much between 1 AU and 5 AU, hence indicating that the rate of opening cannot be easily described by simple models previously proposed, and motivated by solar observations. The degree of openness of the fields at 1 AU and 5 AU implies that the fields open slowly, raising the issue of a flux catastrophe: an unbounded buildup of flux in the outer heliosphere. Recently, Owens and Crooker [2006] (OC06) derived reconnection times for the decay of closed fields in ICMEs to have timescales of ~50 days. In this paper, we argue that reconnection timescales must be on the order of 10 days or less, in order to prevent an overwhelming buildup of magnetic flux in the heliosphere. In order to facilitate comparisons with OC06 we approach this investigation by starting with a simplified view where CMEs are released at uniform time intervals with uniform strengths. We then evolve our model to include observed ICME rates and representative ICME strengths. We conclude that in order to match observed variations in the heliospheric flux over the solar cycle, reconnection times must be under 10 days, which is much lower than previously derived by OC06. These results directly contradict the findings from CSEs and raise important questions regarding their nature and our understanding of the interaction of the solar magnetic fields as they expand into the heliosphere.
DE: 2100 INTERPLANETARY PHYSICS
DE: 2101 Coronal mass ejections (7513)
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Joint Assembly