On the ion composition properties in the solar wind from the north and south polar coronal holes
Abstract
During Years 2005-2007 in the declining phase of Cycle 23 there were frequent appearances of equatorial coronal holes (CHs) and low-latitude extension of polar CHs that were the source regions of the solar wind measured in-situ at L1 a few days after these CHs past the central meridian. We find that the solar wind heavy ions emanating from the south and north polar CHs have distinct composition properties. Specifically, the charge states measured by ACE/SWICS were systematically lower for solar wind ions from the south polar CHs than those from the north polar CHs, regardless of the solar wind speed. Interestingly, earlier work based on Ulysses data during the declining/minimum phase of Cycle 22 found that it was the north polar CH that was associated with lower solar wind charge states, opposite to what we found in the following solar cycle. We present these results and search for solar properties that may be factors that govern this north-south difference. Implications in solar wind formation are discussed.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2011)
- Pub Date:
- July 2011
- Bibcode:
- 2011shin.confE.158K