Solar Physics

, Volume 256, Issue 1, pp 345–363

Effects of the Weak Polar Fields of Solar Cycle 23: Investigation Using OMNI for the STEREO Mission Period

Authors

    • Space Sciences LaboratoryUniversity of California
    • Department of Earth and Planetary ScienceUniversity of California
  • J. G. Luhmann
    • Space Sciences LaboratoryUniversity of California
  • X. P. Zhao
    • W. W. Hansen Experimental Physics LaboratoryStanford University
  • Y. Liu
    • W. W. Hansen Experimental Physics LaboratoryStanford University
  • P. Riley
    • Predictive Science, Inc.
  • C. N. Arge
    • Air Force Research Laboratory/Space Vehicles Directorate
  • C. T. Russell
    • Institute of Geophysics and Planetary PhysicsUniversity of California
  • I. de Pater
    • Department of Earth and Planetary ScienceUniversity of California
Open AccessSTEREO SCIENCE RESULTS AT SOLAR MINIMUM

DOI: 10.1007/s11207-009-9345-6

Cite this article as:
Lee, C.O., Luhmann, J.G., Zhao, X.P. et al. Sol Phys (2009) 256: 345. doi:10.1007/s11207-009-9345-6

Abstract

The current solar cycle minimum seems to have unusual properties that appear to be related to weak solar polar magnetic fields. We investigate signatures of this unusual polar field in the ecliptic near-Earth interplanetary magnetic field (IMF) for the STEREO period of observations. Using 1 AU OMNI data, we find that for the current solar cycle declining phase to minimum period the peak of the distribution for the values of the ecliptic IMF magnitude is lower compared to a similar phase of the previous solar cycle. We investigate the sources of these weak fields. Our results suggest that they are related to the solar wind stream structure, which is enhanced by the weak polar fields. The direct role of the solar field is therefore complicated by this effect, which redistributes the solar magnetic flux at 1 AU nonuniformly at low to mid heliolatitudes.

Keywords

STEREO mission Solar wind Solar cycle, models Solar cycle, observations Magnetic fields, observations Magnetic fields, interplanetary

Copyright information

© The Author(s) 2009