Solar abundances from X-ray flare observations

Veck, N. J.; Parkinson, J. H.

doi:10.1093/mnras/197.1.41

Cited by 59 publications

(42 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…10 ments with eV. Similar results were obtained by Bre-FIP 1 10 neman & Stone (1985), Cook, Stone, & Vogt (1984), Meyer (1985Meyer ( , 1991, Veck & Parkinson (1981), Schmidt, Bochsler, &Geiss (1988), andFeldman (1992). Meyer (1991) stresses that this division is strictly according to FIP and thus is completely independent of both mass and charge.…”

Section: Introductionsupporting

confidence: 66%

Abundance Modification by the Diamagnetic Effect

Steinitz

Kunoff

1999

The Astrophysical Journal

View full text Add to dashboard Cite

Abundances of elements with first ionization potential (FIP) less than 10 eV in the corona and solar wind are augmented relative to the solar photosphere. This enhancement has been found to be independent of both mass and charge. We emphasize two facts that are relevant to this problem: (1) Only elements with eV are FIP ! 10 already ionized in the chromosphere, while in the corona, all elements are ionized. (2) It is known that diverging magnetic field structures anchored in the photosphere pass to the chromosphere (e.g., sunspots). Considering these facts, we construct a model in which the combination of the diamagnetic effect and gravity will pump charged particles, but not neutrals, from the chromosphere into the corona, thus producing the observed enhancement of low-versus high-FIP elements. This charged particle pump is operational irrespective of the existence of other mechanisms that have been proposed previously. Qualitative agreement is obtained with observed abundance ratios in the Sun and several stars.

show abstract

Section: Introductionsupporting

confidence: 66%

Abundance Modification by the Diamagnetic Effect

Steinitz

Kunoff

1999

The Astrophysical Journal

View full text Add to dashboard Cite

show abstract

“…Sulfur, on the other hand, might need to be lowered to ∼65% of its current value. The lower sulfur abundance is consistent with the spectroscopic measurements from Veck & Parkinson (1981) and Fludra & Schmelz (1999), but at odds with the SEP data from Reames (1995) and the solar wind data from von Steiger et al (2000Steiger et al ( , 2010. Abundance results for this intermediate-FIP element are difficult to pin down, and further analysis will be required to sort out this problem.…”

Section: Fip Effectsupporting

confidence: 51%

Deriving Plasma Densities and Elemental Abundances From Serts Differential Emission Measure Analysis

Schmelz

Kimble

Saba

2012

ApJ

View full text Add to dashboard Cite

We use high-resolution spectral emission line data obtained by the SERTS instrument during three rocket flights to demonstrate a new approach for constraining electron densities of solar active region plasma. We apply differential emission measure (DEM) forward-fitting techniques to characterize the multithermal solar plasma producing the observed EUV spectra, with constraints on the high-temperature plasma from the Yohkoh Soft X-ray Telescope. In this iterative process, we compare line intensities predicted by an input source distribution to observed line intensities for multiple iron ion species, and search a broad range of densities to optimize χ 2 simultaneously for the many available density-sensitive lines. This produces a density weighted by the DEM, which appears to be useful for characterizing the bulk of the emitting plasma over a significant range of temperature. This "DEM-weighted density" technique is complementary to the use of density-sensitive line ratios and less affected by uncertainties in atomic data and ionization fraction for any specific line. Once the DEM shape and the DEM-weighted density have been established from the iron lines, the relative elemental abundances can be determined for other lines in the spectrum. We have also identified spectral lines in the SERTS wavelength range that may be problematic.

show abstract

“…A list of the lines (and intensities) used for this purpose is provided in One of the aims of our study was to investigate the effect of varying elemental abundances on the XRT channels. Veck & Parkinson (1981) found that low first ionisation potential (FIP) elements seem to have photospheric values, and that high-FIP elements seem to be depleted, using line-to-continuum X-ray measurements of solar flares observed by the Orbiting Solar Observatory (OSO)-8. Since then, a large body of literature on variations of coronal abundances (compared to their photospheric values) has been presented.…”

Section: Observations and Data Analysismentioning

confidence: 99%

Response of Hinode XRT to quiet Sun, active region and flare plasma

O’Dwyer¹,

Zanna²,

Mason³

2013

A&A

View full text Add to dashboard Cite

Aims. We examine the response of the Hinode X-Ray Telescope (XRT), using simultaneous observations with the Hinode Extremeultraviolet Imaging Spectrometer (EIS), for a flare, an active region and a quiet Sun region. We also examine the relative intensity calibration of EIS and XRT. Methods. EIS differential emission measure distribution (DEM) curves were used to create synthetic spectra with the CHIANTI atomic database. The contribution of spectral lines and continuum emission to each of the XRT channels was determined from the synthetic spectra, which were then convolved with the effective area of each XRT channel. The predicted total count rates for each channel were compared with the observed count rates. The effects of varying elemental abundances and the temperature range for the inversion were investigated. DEMs obtained from the XRT bands were also computed and compared to those obtained with EIS.Results. For the active region observations, the observed XRT count rates for most of the channels are in reasonable agreement with those predicted using EIS observations, but are dependent on the elemental abundances chosen. Significant discrepancies between predicted and observed count rates were found and are discussed for the adjacent quiet Sun region and also for the flare. Synthetic spectra and continuum emission contributing to the XRT channels are presented and discussed for the active region, quiet Sun and flare observations.

show abstract

Solar abundances from X-ray flare observations

Cited by 59 publications

References 0 publications

Abundance Modification by the Diamagnetic Effect

Abundance Modification by the Diamagnetic Effect

Deriving Plasma Densities and Elemental Abundances From Serts Differential Emission Measure Analysis

Response of Hinode XRT to quiet Sun, active region and flare plasma

Contact Info

Product

Resources

About