Isothermal and Multithermal Analysis of Coronal Loops Observed With Aia

Schmelz, J. T.; Jenkins, B. S.; Worley, B. T.; Anderson, David J.; Pathak, S.; Kimble, J. A.

doi:10.1088/0004-637x/731/1/49

Cited by 47 publications

(35 citation statements)

References 19 publications

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“…This code was first written for processing Hinode X-ray Telescope data Weber et al 2004), and then modified for handling SDO/AIA data (Schmelz et al 2011;Cheng et al 2012). In this letter, log T is set in the range of 5.7-7.3, where the DEM is generally well constrained (Aschwanden & Boerner 2011, Hannah & Kontar 2012.…”

Section: Observations and Methodsmentioning

confidence: 99%

Simultaneous Observation of a Flux Rope Eruption and Magnetic Reconnection during an X-class Solar Flare

Yan

Yang

Xue

et al. 2018

ApJL

130

103

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In this letter, we present a spectacular eruptive flare (X8.2) associated with a coronal mass ejection (CME) on 2017 September 10 at the west limb of the Sun. A flux rope eruption is followed by the inflow, the formation of a current sheet and a cusp structure, which were simultaneously observed during the occurrence of this flare. The hierarchical layers of the cusp-shaped structure are well observed in 131Å observation. The scenario that can be created from these observations is very consistent with the predictions of some eruptive models. Except for the characteristics mentioned above in the process of the flare predicted by classical eruption models, the current sheet separating into several small current sheets is also observed at the final stage of the flux rope eruption. The quantitative calculation of the velocities and accelerations of the inflow, hot cusp structure, and post-flare loops is presented. The width of the current sheet is estimated to be about 3 × 10 3 km. These observations are very useful to understand the process of solar eruptions.

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Section: Observations and Methodsmentioning

confidence: 99%

Simultaneous Observation of a Flux Rope Eruption and Magnetic Reconnection during an X-class Solar Flare

Yan

Yang

Xue

et al. 2018

ApJL

130

103

View full text Add to dashboard Cite

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“…Significant problems in the 94 Å band were reported by several authors (see, e.g. Aschwanden & Boerner 2011;Del Zanna et al 2011c;Schmelz et al 2011;Foster & Testa 2011;Testa et al 2012b), but it was not clear if these were due to calibration or atomic data issues, so a few authors produced empirical estimates for the Fe xviii emission (Reale et al 2011;Testa & Reale 2012;Warren et al 2012).…”

Section: Aia 94 åmentioning

confidence: 99%

The multi-thermal emission in solar active regions

Zanna¹

2013

A&A

159

110

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We present simultaneous SDO AIA and Hinode EIS observations of the hot cores of active regions (ARs) and assess the dominant contributions to the AIA EUV bands. This is an extension of our previous work. We find good agreement between SDO AIA, EVE and EIS observations, using our new EIS calibration and the latest EVE v.3 data. We find that all the AIA bands are multi-thermal, with the exception of the 171 and 335 Å, and provide ways to roughly estimate the main contributions directly from the AIA data. We present and discuss new atomic data for the AIA bands, showing that they are now sufficiently complete to obtain temperature information in the cores of ARs, with the exception of the 211 Å band. We found that the newly identified Fe xiv 93.61 Å line is the dominant contribution to the 94 Å band, whenever Fe xviii is not present. Three methods to estimate the Fe xviii emission in this band are presented, two using EIS and one directly from the AIA data. Fe xviii emission is often present in the cores of ARs, but we found cases where it is formed at 3 MK and not 7 MK, the temperature of peak ion abundance in equilibrium. The best EIS lines for elemental abundance determination and differential emission measure (DEM) analysis are discussed. A new set of abundances for many elements are obtained from EIS observations of hot 3 MK loops. The abundances of the elements with low first ionisation potential (FIP), relative to those of the high-FIP elements, are found to be enhanced by about a factor of three, compared to the photospheric values. A measurement of the path length implies that the absolute abundances of the low-FIP elements are higher than the photospheric values by at least a factor of three. We present a new DEM method customised for the AIA bands, to study the thermal structure of ARs at 1 resolution. This was tested on a few ARs, including one observed during the Hi-C rocket flight. We found excellent agreement between predicted and observed AIA count rates and EIS radiances. Overall we found few differences between the AIA and Hi-C 193 Å images of coronal structures, despite the higher Hi-C resolution (0.25 ). The Hi-C images and the AIA DEM modelling suggest that some of the cooler loops (below 1 MK) are already resolved by AIA, while the hotter (1.5-2.5 MK) "background" emission is in most places still unresolved even at the Hi-C resolution. This unresolved emission is significantly lower than previously observed with TRACE, the SOHO CDS, and Hinode EIS spectrometers. Its enhancement appears to be mostly due to increased iron abundance. We find an ubiquitous presence of emission at different temperatures that is not co-spatial, and suggest that future high-resolution imaging is carried out with isothermal bands.

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“…Although EUV telescope images are commonly called by the peak emission temperature of their dominant spectral lines, or by those lines themselves (e.g., "Fe ix/x" or "1 MK" for the 171 Å images from EUVI), some bright features may be at a different temperature entirely (e.g., DeForest et al 1991), and in the presence of flow the ionization equilibrium can be very different from the static case (e.g., Esser et al 1992;Habbal et al 1993). Nevertheless, because most coronal structures appear to be multithermal (e.g., DeForest 1995; Schmelz et al 2011 and references therein), and because the plasma β parameter is low in most of the corona, EUV imagery makes a good first-impression diagnostic of both density and magnetic morphology. Features such as cusps and X-points are directly visible morphologically.…”

Section: Secchi/euvi and The Cme Onset Mechanismmentioning

confidence: 99%

Tracking Coronal Features From the Low Corona to Earth: A Quantitative Analysis of the 2008 December 12 Coronal Mass Ejection

DeForest

Howard

McComas

2013

ApJ

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We have tracked a slow magnetic cloud associated coronal mass ejection (CME) continuously from its origin as a flux rope structure in the low solar corona over a four-day passage to impact with spacecraft located near Earth. Combining measurements from the STEREO, ACE, and Wind space missions, we are able to follow major elements with enough specificity to relate pre-CME coronal structure in the low corona to the corresponding elements seen in the near-Earth in situ data. Combining extreme ultraviolet imaging, quantitative Thomson scattering data throughout the flight of the CME, and "ground-truth" in situ measurements, we: (1) identify the plasma observed by ACE and Wind with specific features in the solar corona (a segment of a long flux rope); (2) determine the onset mechanism of the CME (destabilization of a filament channel following flare reconnection, coupled with the mass draining instability) and demonstrate that it is consistent with the in situ measurements; (3) identify the origin of different layers of the sheath material around the central magnetic cloud (closed field lifted from the base of the corona, closed field entrained during passage through the corona, and solar wind entrained by the front of the CME); (4) measure mass accretion of the system via snowplow effects in the solar wind as the CME crossed the solar system; and (5) quantify the kinetic energy budget of the system in interplanetary space, and determine that it is consistent with no long-term driving force on the CME.

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Isothermal and Multithermal Analysis of Coronal Loops Observed With Aia

Cited by 47 publications

References 19 publications

Simultaneous Observation of a Flux Rope Eruption and Magnetic Reconnection during an X-class Solar Flare

Simultaneous Observation of a Flux Rope Eruption and Magnetic Reconnection during an X-class Solar Flare

The multi-thermal emission in solar active regions

Tracking Coronal Features From the Low Corona to Earth: A Quantitative Analysis of the 2008 December 12 Coronal Mass Ejection

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