NON-WKB MODELS OF THE FIRST IONIZATION POTENTIAL EFFECT: IMPLICATIONS FOR SOLAR CORONAL HEATING AND THE CORONAL HELIUM AND NEON ABUNDANCES

Journal Article · Mon Apr 20 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/695/2/954; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21296247

Laming, J Martin ^[1]

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1. Space Science Division, Naval Research Laboratory Code 7674L, Washington, DC 20375 (United States)

We revisit in more detail a model for element abundance fractionation in the solar chromosphere that gives rise to the 'first ionization potential (FIP) effect' in the solar corona and wind. Elements with first ionization potential below about 10 eV, i.e., those that are predominantly ionized in the chromosphere, are enriched in the corona by a factor of 3-4. We model the propagation of Alfven waves through the chromosphere using a non-WKB treatment, and evaluate the ponderomotive force associated with these waves. Under solar conditions, this is generally pointed upward in the chromosphere, and enhances the abundance of chromospheric ions in the corona. Our new approach captures the essentials of the solar coronal abundance anomalies, including the depletion of He relative to H, and also the putative depletion of Ne, recently discussed in the literature. We also argue that the FIP effect provides the strongest evidence to date for energy fluxes of Alfven waves sufficient to heat the corona. However, it appears that these waves must also be generated in the corona, in order to preserve the rather regular fractionation pattern without strong variations from loop to loop observed in the solar corona and slow-speed solar wind.

• OSTI ID: 21296247
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 695; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ALFVEN WAVES
CHROMOSPHERE
ELEMENT ABUNDANCE
FRACTIONATION
HELIUM
IONIZATION POTENTIAL
NEON
PONDEROMOTIVE FORCE
SOLAR CORONA
SOLAR WIND
SUN
TURBULENCE