COR1 inner coronagraph for STEREO-SECCHI

Thompson, W. T.; Davila, J. M.; Fisher, Richard R.; Orwig, L. E.; Mentzell, John Eric; Hetherington, Samuel E.; Derro, Rebecca J.; Federline, Robert E.; Clark, David; Chen, Philip T. C.; Tveekrem, June L.; Martino, Anthony J.; Novello, Joseph; Wesenberg, R. P.; StCyr, O. C.; Reginald, N. L.; Howard, R. A.; Mehalick, Kimberly I.; Hersh, Michael J.; Newman, Miles; Thomas, Debbie L.; Card, G.; Elmore, D.

doi:10.1117/12.460267

Cited by 84 publications

(23 citation statements)

References 9 publications

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“…We focus here on EUV data and total brightness white-light images collected by the EUVI and the COR1 coronagraph (Thompson et al, 2003) on SECCHI, respectively. EUVI takes full-disk images in EUV channels centered around 171, 195, 284, and 304 Å (hereafter referred as 171, 195, 284, and 304).…”

Section: Observations and Data Analysismentioning

confidence: 99%

What Is the Nature of EUV Waves? First STEREO 3D Observations and Comparison with Theoretical Models

et al. 2009

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One of the major discoveries of the Extreme ultraviolet Imaging Telescope (EIT) on SOHO was the intensity enhancements propagating over a large fraction of the solar surface. The physical origin(s) of the so-called EIT waves is still strongly debated with either wave (primarily fast-mode MHD waves) or nonwave (pseudo-wave) interpretations. The difficulty in understanding the nature of EUV waves lies in the limitations of the EIT observations that have been used almost exclusively for their study. They suffer from low cadence and single temperature and viewpoint coverage. These limitations are largely overcome by the SECCHI/EUVI observations onboard the STEREO mission. The EUVI telescopes provide high-cadence, simultaneous multitemperature coverage and two well-separated viewpoints. We present here the first detailed analysis of an EUV wave observed by the EUVI disk imagers on 7 December 2007 when the STEREO spacecraft separation was ≈ 45°. Both a small flare and a coronal mass ejection (CME) were associated with the wave. We also offer the first comprehensive comparison of the various wave interpretations against the observations. Our major findings are as follows: (1) High-cadence (2.5-minute) 171 Å images showed a strong association between expanding loops and the wave onset and significant STEREO Science Results at Solar Minimum S. Patsourakos et al.differences in the wave appearance between the two STEREO viewpoints during its early stages; these differences largely disappeared later; (2) the wave appears at the active region periphery when an abrupt disappearance of the expanding loops occurs within an interval of 2.5 minutes; (3) almost simultaneous images at different temperatures showed that the wave was most visible in the 1 -2 MK range and almost invisible in chromospheric/transition region temperatures; (4) triangulations of the wave indicate it was rather low lying (≈ 90 Mm above the surface); (5) forward-fitting of the corresponding CME as seen by the COR1 coronagraphs showed that the projection of the best-fit model on the solar surface was inconsistent with the location and size of the co-temporal EUV wave; and (6) simulations of a fast-mode wave were found in good agreement with the overall shape and location of the observed wave. Our findings give significant support for a fast-mode interpretation of EUV waves and indicate that they are probably triggered by the rapid expansion of the loops associated with the CME.

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Section: Observations and Data Analysismentioning

confidence: 99%

What Is the Nature of EUV Waves? First STEREO 3D Observations and Comparison with Theoretical Models

et al. 2009

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“…Images taken in the 195 Å passband have a nominal cadence of 10 minutes, which has increased to 5 minutes in 2009. The evolution of the CME further away from the Sun was followed in data from the STEREO COR1 and COR2 coronagraphs (Thompson et al 2003). COR1 has a field of view (FOV) from 1.4 to 4 R from Sun center and COR2 from 2.5 to 15 R .…”

Section: Observationsmentioning

confidence: 99%

Relation Between the Coronal Mass Ejection Acceleration and the Non-Thermal Flare Characteristics

Berkebile-Stoiser

Veronig

Bein

et al. 2012

ApJ

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We investigate the relationship between the main acceleration phase of coronal mass ejections (CMEs) and the particle acceleration in the associated flares as evidenced in Reuven Ramaty High Energy Solar Spectroscopic Imager non-thermal X-rays for a set of 37 impulsive flare-CME events. Both the CME peak velocity and peak acceleration yield distinct correlations with various parameters characterizing the flare-accelerated electron spectra. The highest correlation coefficient is obtained for the relation of the CME peak velocity and the total energy in accelerated electrons (c = 0.85), supporting the idea that the acceleration of the CME and the particle acceleration in the associated flare draw their energy from a common source, probably magnetic reconnection in the current sheet behind the erupting structure. In general, the CME peak velocity shows somewhat higher correlations with the non-thermal flare parameters than the CME peak acceleration, except for the spectral index of the accelerated electron spectrum, which yields a higher correlation with the CME peak acceleration (c ≈ −0.6), indicating that the hardness of the flare-accelerated electron spectrum is tightly coupled to the impulsive acceleration process of the rising CME structure. We also obtained high correlations between the CME initiation height h 0 and the non-thermal flare parameters, with the highest correlation of h 0 to the spectral index δ of flare-accelerated electrons (c ≈ 0.8). This means that CMEs erupting at low coronal heights, i.e., in regions of stronger magnetic fields, are accompanied by flares that are more efficient at accelerating electrons to high energies. In the majority of events (∼80%), the non-thermal flare emission starts after the CME acceleration, on average delayed by ≈6 minutes, in line with the standard flare model where the rising flux rope stretches the field lines underneath until magnetic reconnection sets in. We find that the current sheet length at the onset of magnetic reconnection is 21 ± 7 Mm. The flare hard X-ray peaks are well synchronized with the peak of the CME acceleration profile, and in 75% of the cases they occur within ±5 minutes. Our findings provide strong evidence for the tight coupling between the CME dynamics and the particle acceleration in the associated flare in impulsive events, with the total energy in accelerated electrons being closely correlated with the peak velocity (and thus the kinetic energy) of the CME, whereas the number of electrons accelerated to high energies is decisively related to the CME peak acceleration and the height of the pre-eruptive structure.

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“…Using the inner coronagraph, COR1 (Thompson et al 2003), of the twin STEREO spacecraft (Kaiser et al 2008), we can make heighttime coronal images (the so-called J-maps; Sheeley et al 1999). The COR1 field of view (FOV) extends as low as 1.4 R , so using this instrument we can lower the threshold altitude at which blobs are observed (previously 2 R ).…”

Section: Introductionmentioning

confidence: 99%

LOCALIZED PLASMA DENSITY ENHANCEMENTS OBSERVED INSTEREOCOR1

Jones

Davila

2009

ApJ

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Measurements of solar wind speed in the solar corona, where it is primarily accelerated, have proven elusive. One of the more successful attempts has been the tracking of outward-moving density inhomogeneities in whitelight coronagraph images. These inhomogeneities, or "blobs," have been treated as passive tracers of the ambient solar wind. Here we report on the extension of these observations to lower altitudes using the STEREO COR1 coronagraph, and discuss the implications of these measurements for theories about the origin of these features.

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COR1 inner coronagraph for STEREO-SECCHI

Cited by 84 publications

References 9 publications

What Is the Nature of EUV Waves? First STEREO 3D Observations and Comparison with Theoretical Models

What Is the Nature of EUV Waves? First STEREO 3D Observations and Comparison with Theoretical Models

Relation Between the Coronal Mass Ejection Acceleration and the Non-Thermal Flare Characteristics

LOCALIZED PLASMA DENSITY ENHANCEMENTS OBSERVED INSTEREOCOR1

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