COHERENT STRUCTURE IN SOLAR WIND C super(6+)/C super(4+) IONIC COMPOSITION DATA DURING THE QUIET-SUN CONDITIONS OF 2008

This analysis offers evidence of characteristic scale sizes in solar wind charge state data measured in situ for 13 quiet-Sun Carrington rotations in 2008. Using a previously established novel methodology, we analyze the wavelet power spectrum of the charge state ratio C super(6+)/C super(4+) measur...

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Bibliographic Details
Published in:The Astrophysical journal 2013-11, Vol.778 (1), p.1-12
Main Authors: Edmondson, J K, Lynch, B J, Lepri, S T, Zurbuchen, T H
Format: Article
Language:English
Subjects:
Charge
Coherence
Extraction
Magnetic fields
Organizing
Solar wind
Wavelet
Wind power generation
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Summary:This analysis offers evidence of characteristic scale sizes in solar wind charge state data measured in situ for 13 quiet-Sun Carrington rotations in 2008. Using a previously established novel methodology, we analyze the wavelet power spectrum of the charge state ratio C super(6+)/C super(4+) measured in situ by ACE/SWICS for 2 hr and 12 minute cadence. We construct a statistical significance level in the wavelet power spectrum to quantify the interference effects arising from filling missing data in the time series, allowing extraction of significant power from the measured data to a resolution of 24 minutes. We analyze each wavelet power spectrum for transient coherency and global periodicities resulting from the superposition of repeating coherent structures. From the significant wavelet power spectra, we find evidence for a general upper limit on individual transient coherency of ~ 10 days. We find evidence for a set of global periodicities between 4-5 hr and 35-45 days. We find evidence for the distribution of individual transient coherency scales consisting of two distinct populations. Below the ~2 day timescale, the distribution is reasonably approximated by an inverse power law, whereas for scales [lap]2 days, the distribution levels off, showing discrete peaks at common coherency scales. In addition, by organizing the transient coherency scale distributions by wind type, we find that these larger, common coherency scales are more prevalent and well defined in coronal hole wind. Finally, we discuss the implications of our results for current theories of solar wind generation and describe future work for determining the relationship between the coherent structures in our ionic composition data and the structure of the coronal magnetic field.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/778/1/44