SECCHI Observations of the Sun's Garden-Hose Density Spiral

Sheeley, N. R.; Herbst, Ashley; Palatchi, C. A.; Wang, Y.-M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, Jeffrey; Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.; Davila, J. M.; Thompson, W. T.; Cyr, O. C. St.; Harrison, R. A.; Davis, CJ; Eyles, C. J.; Halain, Jean-Philippe; Wang, D.; Rich, N.; Battams, K.; Esfandiari, E.; Stenborg, G.

doi:10.1086/529020

Cited by 63 publications

(92 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…-the discovery of the atomic ion tail of Comet McNaught (Fulle et al, 2007), -a direct observation of the interaction between a CME and a comet (Comet Encke), leading to the complete disconnection of the comet's plasma tail (Vourlidas et al, 2007), -observations of the structure of the solar wind, in particular the first direct white-light images of corotating interaction regions in the interplanetary medium (Rouillard et al, 2008;Sheeley et al, 2008aSheeley et al, , 2008b, -the first observation of the planetary impact of a CME by the STEREO spacecraft confirmed by in situ measurements by the magnetometer aboard the Venus Express spacecraft (Rouillard et al, 2009), and -stellar variability studies (Bewsher et al, in preparation).…”

Section: Resultsmentioning

confidence: 99%

The Heliospheric Imagers Onboard the STEREO Mission

et al. 2008

Self Cite

View full text Add to dashboard Cite

Mounted on the sides of two widely separated spacecraft, the two Heliospheric Imager (HI) instruments onboard NASA's STEREO mission view, for the first time, the space between the Sun and Earth. These instruments are wide-angle visible-light imagers that incorporate sufficient baffling to eliminate scattered light to the extent that the passage of solar coronal mass ejections (CMEs) through the heliosphere can be detected. Each HI instrument comprises two cameras, HI-1 and HI-2, which have 20°and 70°fields of view and are off-pointed from the Sun direction by 14.0°and 53.7°, respectively, with their optical axes aligned in the ecliptic plane. This arrangement provides coverage over solar elongation angles from 4.0°to 88.7°at the viewpoints of the two spacecraft, thereby allowing the observation of Earth-directed CMEs along the Sun -Earth line to the vicinity of the Earth and beyond. Given the two separated platforms, this also presents the first opportunity to view the structure and evolution of CMEs in three dimensions. The STEREO spacecraft were launched from Cape Canaveral Air Force Base in late October 2006, and the HI instruments have been performing scientific observations since early 2007. The design, development, manufacture, and calibration of these unique instruments are reviewed in this paper. Mission operations, including the initial commissioning phase and the science operations phase, are described. Data processing and analysis procedures are briefly discussed, and groundtest results and in-orbit observations are used to demonstrate that the performance of the instruments meets the original scientific requirements.

show abstract

Section: Resultsmentioning

confidence: 99%

The Heliospheric Imagers Onboard the STEREO Mission

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…It should be mentioned that the slowly moving faint fronts seen out ahead of the red arrows in the two HI2-A images appear to us to be possible signatures of a corotating interaction region (CIR) that is also moving through the IPM at the time of the CME, a complicating factor in the interpretation of the HI2 images. Sheeley et al (2008aSheeley et al ( , 2008b and Rouillard et al (2008) have previously described the appearance of CIRs in HI2 data.…”

Section: The Ipm Appearance Of the April 26 Cmementioning

confidence: 91%

An Empirical Reconstruction of the 2008 April 26 Coronal Mass Ejection

Wood

Howard

2009

ApJ

Self Cite

View full text Add to dashboard Cite

We present a three-dimensional model of the density distribution of a coronal mass ejection (CME) from 2008 April 26. This CME was observed by the two spacecraft composing the Solar Terrestrial Relations Observatory (STEREO), which tracked the CME from near the Sun, into the interplanetary medium (IPM), and all the way to 1 AU. The CME was directed toward STEREO-B and hit that spacecraft on 2008 April 29. The STEREO images of the CME show an internal structure that can be interpreted as having a flux rope shape. The two different perspectives on the event provided by the two STEREO spacecraft allow us to make a particularly strong argument for the flux rope interpretation, and the STEREO data also allow us to study the evolution of the flux rope in the IPM. The flux rope is oriented close to the ecliptic plane, but with the western leg tilted northwards by about 20 • . This implies an orientation roughly perpendicular to the neutral line of the active region at the event's point of origin, apparently an unusual geometry given that previous analyses have found that CME flux ropes are usually, but not always, oriented parallel to the neutral lines of their source regions. The CME model also consists of a front out ahead of the flux rope, possibly a shock launched by the flux rope driver. The model density distribution is reasonably successful at reproducing the CME appearance both close to the Sun in coronagraphic images, and far from the Sun in images of the IPM from STEREO's heliospheric imagers. This suggests that self-similar expansion is a reasonable first-order approximation for this particular CME, and also indicates that the flux rope's orientation does not change much during its journey through the IPM.

show abstract

“…Analogous to the time-elongation plot commonly used to track CMEs with coronagraph observations (e.g., Sheeley et al 2008;Lugaz et al 2009), we construct these diagnostics by first extracting the EUV signal along a Sun-centered circular arc of radius r = 1.1 R off of the East limb for every image in the dataset. The ratio of the EUV flux along this arc to the flux for the preceding image for a given filter is then calculated.…”

Section: Time-distance Limb Diagramsmentioning

confidence: 99%

Studying Extreme Ultraviolet Wave Transients With a Digital Laboratory: Direct Comparison of Extreme Ultraviolet Wave Observations to Global Magnetohydrodynamic Simulations

Downs

Roussev

Holst

et al. 2011

ApJ

View full text Add to dashboard Cite

In this work, we describe our effort to explore the signatures of large-scale extreme ultraviolet (EUV) transients in the solar corona (EUV waves) using a three-dimensional thermodynamic magnetohydrodynamic model. We conduct multiple simulations of the 2008 March 25 EUV wave (∼18:40 UT), observed both on and off of the solar disk by the STEREO-A and B spacecraft. By independently varying fundamental parameters thought to govern the physical mechanisms behind EUV waves in each model, such as the ambient magneto-sonic speed, eruption free energy, and eruption handedness, we are able to assess their respective contributions to the transient signature. A key feature of this work is the ability to synthesize the multi-filter response of the STEREO Extreme UltraViolet Imagers directly from model data, which gives a means for direct interpretation of EUV observations with full knowledge of the three-dimensional magnetic and thermodynamic structures in the simulations. We discuss the implications of our results with respect to some commonly held interpretations of EUV waves (e.g., fast-mode magnetosonic wave, plasma compression, reconnection front, etc.) and present a unified scenario which includes both a wave-like component moving at the fast magnetosonic speed and a coherent driven compression front related to the eruptive event itself.

show abstract

SECCHI Observations of the Sun's Garden-Hose Density Spiral

Cited by 63 publications

References 3 publications

The Heliospheric Imagers Onboard the STEREO Mission

The Heliospheric Imagers Onboard the STEREO Mission

An Empirical Reconstruction of the 2008 April 26 Coronal Mass Ejection

Studying Extreme Ultraviolet Wave Transients With a Digital Laboratory: Direct Comparison of Extreme Ultraviolet Wave Observations to Global Magnetohydrodynamic Simulations

Contact Info

Product

Resources

About