Physics of outflows near solar active regions

Price, Daniel J.; Taroyan, Y.

doi:10.5194/angeo-33-25-2015

Cited by 4 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They argue the model could reproduce observed downflows and broad DEM distribution along the loops (Schmelz et al 2001). Similarly, other models have investigated the many-stranded nature of coronal loops and the impulsive heating through nanoflare events (Cargill & Klimchuk 2004;Sarkar & Walsh 2008Taroyan et al 2011;Price & Taroyan 2015).…”

Section: Introductionmentioning

confidence: 99%

Is the High-Resolution Coronal Imager Resolving Coronal Strands? Results from AR 12712

Williams

Walsh

Winebarger

et al. 2020

ApJ

View full text Add to dashboard Cite

Following the success of the first mission, the High-Resolution Coronal Imager (Hi-C) was launched for a third time (Hi-C 2.1) on 29 th May 2018 from the White Sands Missile Range, NM, USA. On this occasion, 329 seconds of 17.2 nm data of target active region AR 12712 was captured with a cadence of ≈ 4 s, and a plate scale of 0.129 pixel. Using data captured by Hi-C 2.1 and co-aligned observations from SDO/AIA 17.1 nm we investigate the widths of 49 coronal strands. We search for evidence of substructure within the strands that is not detected by AIA, and further consider whether these strands are fully resolved by Hi-C 2.1. With the aid of Multi-Scale Gaussian Normalization (MGN), strands from a region of low-emission that can only be visualized against the contrast of the darker, underlying moss are studied. A comparison is made between these low-emission strands with those from regions of higher emission within the target active region. It is found that Hi-C 2.1 can resolve individual strands as small as ≈ 202 km, though more typical strands widths seen are ≈ 513 km. For coronal strands within the region of low-emission, the most likely width is significantly narrower than the high-emission strands at ≈ 388 km. This places the low-emission coronal strands beneath the resolving capabilities of SDO/AIA, highlighting the need of a permanent solar observatory with the resolving power of Hi-C.

show abstract

Section: Introductionmentioning

confidence: 99%

Is the High-Resolution Coronal Imager Resolving Coronal Strands? Results from AR 12712

Williams

Walsh

Winebarger

et al. 2020

ApJ

View full text Add to dashboard Cite

show abstract

“…However, 1D simulations are still greatly useful, particularly those which model a multistranded structure as opposed to monolithic loops. For example, Price and Taroyan (2015) forward model the synthetic profiles of a well-documented Hinode/EIS structure (McIntosh and De Pontieu, 2009) using various numbers of sub-element strands to try and deduce the nature of the outflows observed. Their results support a scenario whereby long loops formed of multiple strands undergo periodic heating and cooling.…”

Section: Introductionmentioning

confidence: 99%

Multi-Stranded Coronal Loops: Quantifying Strand Number and Heating Frequency from Simulated Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) Observations

et al. 2021

View full text Add to dashboard Cite

Coronal loops form the basic building blocks of the magnetically closed solar corona yet much is still to be determined concerning their possible fine-scale structuring and the rate of heat deposition within them. Using an improved multi-stranded loop model to better approximate the numerically challenging transition region, this article examines synthetic NASA Solar Dynamics Observatory’s (SDO) Atmospheric Imaging Assembly (AIA) emission simulated in response to a series of prescribed spatially and temporally random, impulsive and localised heating events across numerous sub-loop elements with a strong weighting towards the base of the structure: the nanoflare heating scenario. The total number of strands and nanoflare repetition times is varied systematically in such a way that the total energy content remains approximately constant across all the cases analysed. Repeated time-lag detection during an emission time series provides a good approximation for the nanoflare repetition time for low-frequency heating. Furthermore, using a combination of AIA 171/193 and 193/211 channel ratios in combination with spectroscopic determination of the standard deviation of the loop-apex temperature over several hours alongside simulations from the outlined multi-stranded loop model, it is demonstrated that both the imposed heating rate and number of strands can be realised.

show abstract

“…However, 1D simulations are still greatly useful, particularly those which model a multi-stranded structure as opposed to monolithic loops. For example, Price & Taroyan (2015) forward model the synthetic profiles of a welldocumented Hinode/EIS structure (McIntosh & De Pontieu, 2009) using various SOLA: main.tex; 27 May 2021; 0:45; p. 3 numbers of sub-element strands to try and deduce the nature of the outflows observed. Their results support a scenario whereby long loops formed of multiple strands undergo periodic heating and cooling.…”

Section: Introductionmentioning

confidence: 99%

Multi-Stranded Coronal Loops: Quantifying Strand Number and Heating Frequency from Simulated Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) Observations

Williams,

Walsh,

Regnier

et al. 2021

Preprint

View full text Add to dashboard Cite

Coronal loops form the basic building blocks of the magnetically closed solar corona yet much is still to be determined concerning their possible fine-scale structuring and the rate of heat deposition within them. Using an improved multi-stranded loop model to better approximate the numerically challenging transition region, this paper examines synthetic NASA Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) emission simulated in response to a series of prescribed spatially and temporally random, impulsive and localised heating events across numerous sub-loop elements with a strong weighting towards the base of the structure; the nanoflare heating scenario. The total number of strands and nanoflare repetition times are varied systematically in such a way that the total energy content remains approximately constant across all the cases analysed. Repeated time lag detection during an emission time series provides a good approximation for the nanoflare repetition time for low-frequency heating. Furthermore, using a combination of AIA 171/193 and 193/211 channel ratios in combination with spectroscopic determination of the standard deviation of the loop apex temperature over several hours alongside simulations from the outlined multi-stranded loop model, it is demonstrated that both the imposed heating rate and number of strands can be realised.

show abstract

Physics of outflows near solar active regions

Cited by 4 publications

References 7 publications

Is the High-Resolution Coronal Imager Resolving Coronal Strands? Results from AR 12712

Is the High-Resolution Coronal Imager Resolving Coronal Strands? Results from AR 12712

Multi-Stranded Coronal Loops: Quantifying Strand Number and Heating Frequency from Simulated Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) Observations

Multi-Stranded Coronal Loops: Quantifying Strand Number and Heating Frequency from Simulated Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) Observations

Contact Info

Product

Resources

About