Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field

Details Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field

Aug 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008apj...683..499w&link_type=abstract

The Astrophysical Journal, Volume 683, Issue 1, pp. 499-509.

Astronomy and Astrophysics

Astronomy

7

Interplanetary Medium, Sun: Solar Wind, Sun: Abundances, Sun: Corona, Sun: Magnetic Fields

Scientific paper

We analyze the long-term variation of the solar wind helium abundance, both in and out of the ecliptic, using stackplot displays to compare these in situ observations with derived coronal parameters. The coronal source regions are identified and their magnetic properties characterized by applying a current-free extrapolation, with source surface located at heliocentric distance r=2.5 Rsolar, to magnetograph measurements. The density ratio AHe of α-particles to protons is found to correlate best with the source-surface field strength Bss, which tends to be enhanced in high-speed flows and in the slow wind at sunspot maximum, but to be weak in the low-speed wind that originates from the polar coronal-hole boundaries around sunspot minimum. A much weaker correlation exists between AHe and the proton flux density at the source surface. These results are consistent with acceleration of the α-particles by ion cyclotron resonance in the outer corona. However, we are unable to explain why the helium abundance was depressed in the recurrent high-speed streams observed in the ecliptic during 1999-2000 and 2003-2004.

Affiliated with

Also associated with

No associations

Rating

Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relating the Solar Wind Helium Abundance to the Coronal Magnetic Field will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1172999