HR: 0800h
AN: SH41A-1115    [Abstracts]
TI: The Invariance of Open Solar Magnetic Flux
AU: * Smith, E J
EM: edward.j.smith @jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109-8099 United States
AU: Zhou, X
EM: xiaoyan.zhou@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109-8099 United States
AB: A major finding of Ulysses has been the relative invariance of the open magnetic flux transported into the heliosphere from the Sun by the solar wind. The measure of open flux, r- squared Br, where r is heliocentric distance and Br is the radial field component, was found to be independent of both heliolatitude and phase of the solar cycle, being essentially the same (to within much less than a factor of two) at the recent sunspot minimum and maximum (cycle #23). Although such an invariance is generally not a feature of models of the solar-heliospheric field, it was predicted by L. Fisk and N. Schwadron who proposed that newly created open flux is the result of merging of already open flux with adjacent magnetic loops so that reconnecting field lines result in another open field and another loop with the total number of each unchanged. Thus, studying the open flux in the solar wind is a test of this hypothesis. The preceding study of open flux by Smith and Balogh ended shortly after solar maximum in 2001 when the polar cap magnetic fields had just reversed and were still relatively weak. Since then, the polar cap fields have strengthened and are now about one-half their value during the previous two sunspot cycles (#21, 22). We now present further evidence regarding this important question in Ulysses data acquired over the past 4 years. The radial components at Ulysses and in-ecliptic spacecraft are compared since the latter measurements are potentially a measure of open flux extending back to previous sunspot cycles.
DE: 2134 Interplanetary magnetic fields
DE: 2162 Solar cycle variations (7536)
DE: 2169 Solar wind sources
DE: 7524 Magnetic fields
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005