Detection of Stellar-like Abundance Anomalies in the Slow Solar Wind

Brooks, David H.; Baker, D.; Driel-Gesztelyi, L. van; Warren, Harry P.; Yardley, Stephanie L.

doi:10.3847/2041-8213/ac6878

Cited by 5 publications

(2 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The waves, which can induce the ponderomotive force, have also been observed in the chromosphere using spectropolarimetric data from the Interferometric Bidimensional Spectrometer instrument and related to coronal FIP bias measurements (Baker et al 2021;Stangalini et al 2021), while both Mihailescu et al (2023) and Murabito et al (2024) have noted a relationship between resonant waves and increased FIP bias via the ponderomotive force. Detections of the IFIP effect in the solar wind also seem to be consistent with the ponderomotive force model of abundance variations, due to chromospheric fastmode waves (Brooks et al 2022).…”

Section: Introductionsupporting

confidence: 79%

Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS

Long,

Baker,

et al. 2024

ApJ

Self Cite

View full text Add to dashboard Cite

The composition of the solar corona differs from that of the photosphere, with the plasma thought to fractionate in the solar chromosphere according to the first ionization potential (FIP) of the different elements. This produces a FIP bias, wherein elements with a low FIP are preferentially enhanced in the corona compared to their photospheric abundance, but direct observations of this process remain elusive. Here, we use a series of spectroscopic observations of active region AR 12759 as it transited the solar disk over a period of 6 days from 2020 April 2–7 taken using the Hinode Extreme ultraviolet Imaging Spectrometer and Interface Region Imaging Spectrograph (IRIS) instruments to look for signatures of plasma fractionation in the solar chromosphere. Using the Si x/S x and Ca xiv/Ar xiv diagnostics, we find distinct differences between the FIP bias of the leading and following polarities of the active region. The widths of the IRIS Si iv lines exhibited clear differences between the leading and following polarity regions, indicating increased unresolved wave activity in the following polarity region compared to the leading polarity region, with the chromospheric velocities derived using the Mg ii lines exhibiting comparable, albeit much weaker, behavior. These results are consistent with plasma fractionation via resonant/nonresonant waves at different locations in the solar chromosphere following the ponderomotive force model, and indicate that IRIS could be used to further study this fundamental physical process.

show abstract

Section: Introductionsupporting

confidence: 79%

Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS

Long,

Baker,

et al. 2024

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the corona of some magnetically active stars low-FIP elements are less abundant than in the photosphere, which shows the depleted low-FIP elements in the corona compared to the photosphere (Brinkman et al 2001;Robrade & Schmitt 2005). Recently, the IFIP effect is also detected in solar flares (Doschek & Warren 2016;Katsuda et al 2020) and slow solar winds (Brooks et al 2022). The observations have revealed that the elemental abundances in the stellar coronae depend on their activity; the low-FIP elements are rich in inactive stars and deficient in active stars (Drake 2002).…”

Section: Elemental Abundances In the Coronamentioning

confidence: 99%

Coronal Loops with Different Metallicities and Generalized RTV Scaling Laws

Washinoue,

Suzuki

2023

ApJ

View full text Add to dashboard Cite

Stellar metallicity is a critical factor to characterize the stellar coronae because it directly affects the radiative energy loss from the atmosphere. By extending theoretical relations for solar coronal loops introduced by Rosner et al., we analytically derive scaling relations for stellar coronal loops with various metallicities. In order to validate the derived relations, we also perform magnetohydrodynamic simulations for the heating of coronal loops with different metallicities by changing radiative-loss functions according to the adopted elemental abundances. The simulation results nicely explain the generalized analytical scaling relations and show a strong dependence of the thermodynamical and radiative properties of the loops on metallicity. Higher density and temperature are obtained in lower-metallicity coronae because of the inefficient radiative cooling, provided that the surface condition is unchanged. Thus, it is estimated that the X-ray radiation from metal-poor coronae is higher because of their denser coronal gas. The generalized scaling laws can also be used as a tool to study the condition of high-energy radiation around magnetically active stars and their impact on planetary environments.

show abstract

Spatially resolved plasma composition evolution in a solar flare – The effect of reconnection outflow

To,

Brooks,

Imada

et al. 2024

A&A

View full text Add to dashboard Cite

Solar flares exhibit complex variations in elemental abundances compared to photospheric values. These abundance variations, characterized by the first ionization potential (FIP) bias, remain challenging to interpret. We aim to 1) examine the spatial and temporal evolution of coronal abundances in the X8.2 flare on 2017 September 10, and 2) provide a new scenario to interpret the often observed high FIP bias loop top, and provide further insight into differences between spatially resolved and Sun-as-a-star flare composition measurements. We analyzed 12 Hinode/Extreme-ultraviolet Imaging Spectrometer (EIS) raster scans spanning 3.5 hours, employing both Ca XIV Ar XIV and Fe XVI S XIII composition diagnostics to derive FIP bias values. We used the Markov Chain Monte Carlo (MCMC) differential emission measure (DEM) method to obtain the distribution of plasma temperatures, which forms the basis for the FIP bias calculations. Both the Ca/Ar and Fe/S composition diagnostics consistently show that flare loop tops maintain high FIP bias values of $>$2--6, with peak phase values exceeding 4, over the extended duration, while footpoints exhibit photospheric FIP bias of sim 1. The consistency between these two diagnostics forms the basis for our interpretation of the abundance variations. We propose that this variation arises from a combination of two distinct processes: high FIP bias plasma downflows from the plasma sheet confined to loop tops, and chromospheric evaporation filling the loop footpoints with low FIP bias plasma. Mixing between these two sources produces the observed gradient. Our observations show that the localized high FIP bias signature at loop tops is likely diluted by the bright footpoint emission in spatially averaged measurements. The spatially resolved spectroscopic observations enabled by EIS prove critical for revealing this complex abundance variation in loops. Furthermore, our observations show clear evidence that the origin of hot flare plasma in flaring loops consists of a combination of both directly heated plasma in the corona and from ablated chromospheric material; and our results provide valuable insights into the formation and composition of loop top brightenings, also known as EUV knots, which are a common feature at the tops of flare loops.

show abstract

Detection of Stellar-like Abundance Anomalies in the Slow Solar Wind

Cited by 5 publications

References 46 publications

Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS

Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS

Coronal Loops with Different Metallicities and Generalized RTV Scaling Laws

Spatially resolved plasma composition evolution in a solar flare – The effect of reconnection outflow

Contact Info

Product

Resources

About