On the 3-D reconstruction of Coronal Mass Ejections using coronagraph data

Mierla, M.; Inhester, B.; Antunes, A.; Boursier, Yannick; Byrne, Jason P.; Colaninno, R. C.; Davila, J. M.; Koning, C. A. de; Gallagher, Peter T.; Gissot, S.; Howard, R. A.; Howard, T. A.; Kramar, Maxim; Lamy, Philippe; Liewer, Paulett C.; Maloney, Shane A.; Marqué, Christophe; McAteer, T. J.; Moran, T.; Rodriguez, L.; Srivastava, Nandita; Cyr, O. C. St.; Stenborg, G.; Temmer, Manuela; Thernisien, A.; Vourlidas, A.; West, Matthew J.; Wood, Brian E.; Zhukov, A. N.

doi:10.5194/angeo-28-203-2010

Cited by 137 publications

(126 citation statements)

References 66 publications

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“…Using white-light measurement of CMEs from these multiple vantage points, Mierla et al (2010) reconstructed the three-dimensional structure of numerous, single CME events from 2007 and 2008. Colaninno & Vourlidas (2015) similarly demonstrated the power of multiple-viewpoint observations by using SOHO, STEREO-A, and STEREO-B to reconstruct the three-dimensional structures of three overlapping and interacting CMEs to shed insight into CME-CME interactions.…”

Section: White-light Imaging Of Cmesmentioning

confidence: 99%

VLA Measurements of Faraday Rotation through Coronal Mass Ejections

et al. 2017

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Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the Sun that play an important role in space weather. Faraday rotation (FR) is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME and is proportional to the path integral through the plasma of the electron density and the line of sight component of the magnetic field.FR observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch; however, separating the contribution of the plasma density from the line of sight magnetic field is challenging.We report on simultaneous white-light and radio observations made of three CMEs in August 2012. We made sensitive Very Large Array (VLA) full-polarization observations using 1 − 2 GHz frequencies of a "constellation" of radio sources through the solar corona at heliocentric distances that ranged from 6 − 15R ⊙ . Of the nine sources observed, three were occulted by CMEs: two sources (0842+1835 and 0900+1832) were occulted by a single CME and one source (0843+1547) was occulted by two CMEs. In addition to our radioastronomical observations, which represent one of the first active hunts for CME Faraday rotation since Bird et al. (2007) and Jensen & Russell (2008), as well as previous CME FR observations by Bird et al. (1985).

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Section: White-light Imaging Of Cmesmentioning

confidence: 99%

VLA Measurements of Faraday Rotation through Coronal Mass Ejections

et al. 2017

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“…The pB/uB ratio can be computed pixel by pixel in the 2D coronagraphic image, thus providing a 3D cloud of points, each point representing the location along z of CME plasma with some kind of unknown LOS averaging. This technique, usually referred to as the polarization-ratio technique, was also validated in the STEREO era (Mierla et al 2010;Moran et al 2010) with comparisons between 3D reconstructions obtained with polarization measurements and other reconstruction methods. Very recently a classification of possible ambiguities arising from polarimetric reconstructions of CMEs depending on the location of CME structures with respect to the POS was given by Dai et al (2014).…”

Section: Introductionmentioning

confidence: 99%

“…Various comparisons between these different methods when applied to the same event have also been performed by some authors for data provided by coronagraphs (see e.g. Mierla et al 2010;Feng et al 2013) and heliospheric imagers (e.g. Mishra et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Uncertainties in polarimetric 3D reconstructions of coronal mass ejections

Бемпорад

Pagano

2015

A&A

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Aims. The aim of this work is to quantify the uncertainties in the three-dimensional (3D) reconstruction of the location of coronal mass ejections (CMEs) obtained with the so-called polarization ratio technique. The method takes advantage of the different distributions along the line of sight of total (tB) and polarized (pB) brightnesses emitted by Thomson scattering to estimate the average location of the emitting plasma. This is particularly important to correctly identify of CME propagation angles and unprojected velocities, thus allowing better capabilities for space weather forecastings. Methods. To this end, we assumed two simple electron density distributions along the line of sight (a constant density and Gaussian density profiles) for a plasma blob and synthesized the expected tB and pB for different distances z of the blob from the plane of the sky and different projected altitudes ρ. Reconstructed locations of the blob along the line of sight were thus compared with the real ones, allowing a precise determination of uncertainties in the method. Results. Results show that, independently of the analytical density profile, when the blob is centered at a small distance from the plane of the sky (i.e. for limb CMEs) the distance from the plane of the sky starts to be significantly overestimated. Polarization ratio technique provides the line-of-sight position of the center of mass of what we call folded density distribution, given by reflecting and summing in front of the plane of the sky the fraction of density profile located behind that plane. On the other hand, when the blob is far from the plane of the sky, but with very small projected altitudes (i.e. for halo CMEs, ρ < 1.4 R ), the inferred distance from that plane is significantly underestimated. Better determination of the real blob position along the line of sight is given for intermediate locations, and in particular when the blob is centered at an angle of 20 • from the plane of the sky. Conclusions. These result have important consequences not only for future 3D reconstruction of CMEs with polarization ratio technique, but also for the design of future coronagraphs aimed at providing a continuous monitoring of halo-CMEs for space weather prediction purposes.

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“…Each instrument provides a two-dimensional (2D) representation of a three-dimensional (3D) CME structure projected into the sky plane. As a consequence, the estimated CME propagation parameters, such as position angle, angular width, height, and speed, are also projected into the same plane (Mierla et al 2010). These CME parameters can be estimated using COR and/or HI images commonly used to assist in space weather forecasting.…”

Section: Introductionmentioning

confidence: 99%

“…The propagation parameters extracted from a single point of view (i.e., one spacecraft) do not give reliable information on the actual CME propagation path. Extraction of the parameters from two vantage points (i.e., both spacecraft), however, makes reconstruction of a true CME propagation path in 3D space possible (Howard & Tappin 2008;Mierla et al 2008Mierla et al , 2010Boursier et al 2009;Colaninno & Vourlidas 2009;de Koning et al 2009; de Koning & Pizzo 2011). The reconstruction can be accomplished using a technique of geometric triangulation, such as that proposed by Liu et al (2010) and Mays et al (2015).…”

Section: Introductionmentioning

confidence: 99%

Combining STEREO SECCHI COR2 and HI1 images for automatic CME front edge tracking

Kirnosov

Chang

Pulkkinen

2016

J. Space Weather Space Clim.

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COR2 coronagraph images are the most commonly used data for coronal mass ejection (CME) analysis among the various types of data provided by the STEREO (Solar Terrestrial Relations Observatory) SECCHI (Sun-Earth Connection Coronal and Heliospheric Investigation) suite of instruments. The field of view (FOV) in COR2 images covers 2-15 solar radii (Rs) that allow for tracking the front edge of a CME in its initial stage to forecast the lead-time of a CME and its chances of reaching the Earth. However, estimating the lead-time of a CME using COR2 images gives a larger lead-time, which may be associated with greater uncertainty. To reduce this uncertainty, CME front edge tracking should be continued beyond the FOV of COR2 images. Therefore, heliospheric imager (HI1) data that covers 15-90 Rs FOV must be included. In this paper, we propose a novel automatic method that takes both COR2 and HI1 images into account and combine the results to track the front edges of a CME continuously. The method consists of two modules: pre-processing and tracking. The pre-processing module produces a set of segmented images, which contain the signature of a CME, for both COR2 and HI1 separately. In addition, the HI1 images are resized and padded, so that the center of the Sun is the central coordinate of the resized HI1 images. The resulting COR2 and HI1 image set is then fed into the tracking module to estimate the position angle (PA) and track the front edge of a CME. The detected front edge is then used to produce a height-time profile that is used to estimate the speed of a CME. The method was validated using 15 CME events observed in the period from January 1, 2008 to August 31, 2009. The results demonstrate that the proposed method is effective for CME front edge tracking in both COR2 and HI1 images. Using this method, the CME front edge can now be tracked automatically and continuously in a much larger range, i.e., from 2 to 90 Rs, for the first time. These improvements can greatly help in making the quantitative CME analysis more accurate and have the potential to assist in space weather forecasting.

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On the 3-D reconstruction of Coronal Mass Ejections using coronagraph data

Cited by 137 publications

References 66 publications

VLA Measurements of Faraday Rotation through Coronal Mass Ejections

VLA Measurements of Faraday Rotation through Coronal Mass Ejections

Uncertainties in polarimetric 3D reconstructions of coronal mass ejections

Combining STEREO SECCHI COR2 and HI1 images for automatic CME front edge tracking

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