Tracking a major interplanetary disturbance with SMEI

Tappin, S. J.; Buffington, A.; Cooke, M. P.; Eyles, C. J.; Hick, P. P.; Holladay, P. E.; Jackson, B. V.; Johnston, J. C.; Kuchar, T. A.; Mizuno, D. R.; Mozer, J. B.; Price, S. D.; Radick, R. R.; Simnett, G. M.; Sinclair, D.; Waltham, N.; Webb, D. F.

doi:10.1029/2003gl018766

Cited by 59 publications

(61 citation statements)

References 5 publications

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“…Thus not only the magnitude but also the sign of the acceleration can be in error. These ICME accelerations are crucial for predicting space weather effects and for modeling the drag or acceleration forces [Tappin et al, 2004;Tappin, 2006;Howard et al, 2006].…”

Section: A3 Comparisons Of Positions and Speeds For The Methodsmentioning

confidence: 99%

V arc interplanetary coronal mass ejections observed with the Solar Mass Ejection Imager

2007

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[1] Since February 2003, the Solar Mass Ejection Imager (SMEI) has been observing interplanetary coronal mass ejections (ICMEs) at solar elongation angles > 20°. The ICMEs generally appear as loops or arcs in the sky, but five show distinct outward concave shapes that we call V arcs. We expect to observe some V arcs, formed by trailing edges of ICME flux ropes or by leading ICME edges sheared by solar wind (SW) speed gradients at the heliospheric current sheet. We characterize the properties of these V arcs and compare them with average properties of all SMEI ICMEs. The typical V arc speeds argue against a slow MHD shock interpretation for their structures. We estimate the V arc solar source locations and their opening angle dynamics as tests for SW shearing. The first test contradicts but the second supports the SW shearing explanation. The implications of the small number of V arcs observed with SMEI is considered. The point P approximation used to determine the V arc locations and inferred solar source regions is critically examined in Appendix A.

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Section: A3 Comparisons Of Positions and Speeds For The Methodsmentioning

confidence: 99%

V arc interplanetary coronal mass ejections observed with the Solar Mass Ejection Imager

2007

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“…However, the SMEI team also produces significant scientific results directly from the 2-D sky map orbit differences (e.g., Tappin et al, 2004;Reiner et al, 2005;Tappin, 2006;Webb et al, 2006Webb et al, , 2009bTappin and Howard, 2009 approximately the same location and morphology of this CME sequence in the ecliptic plane from both instruments as it moves outward from the Sun (e.g., Webb et al, 2009a). These CMEs were also viewed and measured nearer the solar surface by the Large Angle Spectrographic Coronagraphs (LASCO) (Brueckner et al, 1995) on board the SOlar and Heliospheric Observatory (SOHO) spacecraft (Domingo et al, 1995) nearer the solar surface.…”

Section: Introductionmentioning

confidence: 99%

SMEI direct, 3-D-reconstruction sky maps, and volumetric analyses, and their comparison with SOHO and STEREO observations

et al. 2009

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Abstract. In this paper we present the results of the analysis of the late January 2007 Coronal Mass Ejection (CME) events recorded by the Solar Mass Ejection Imager (SMEI), the Solar TErrestrial RElations Observatory (STEREO), and the SOlar and Heliospheric Observatory (SOHO) spacecraft. This period occurs when the two STEREO spacecraft views are from close to Earth, and thus the views from both SMEI and the STEREO outer Heliospheric Imagers (HI-2s) coincide. Three-dimensional (3-D) analyses derived from SMEI data show many CMEs that have also been studied by others using short-term image subtractions (image-differencing techniques). During this interval we map several CME structures that are observed in both SMEI and the STEREO-A HI instruments. SMEI brightness analyses provided by shortterm image subtractions ("difference images") and, alternatively, subtractions of a mean-brightness fit over a long-time duration, both show the extents of the CMEs travelling outward above the East limb that erupted from the Sun on 24 and 25 January 2007. The SMEI 3-D-reconstructions not only enhance distinct features within the CME events, but also reconcile difference-imaging results with those where a long-term base has been removed. In the January 2007 example the structure as mapped by CME difference images traces the sharp intensity gradients at the front of the CMEs; generally brighter ejected material follows behind the location of the CME front, but shows poorly in these because of its larger angular extent. Using the long-duration background removal enables SMEI's 3-D analysis to determine a mass for this CME sequence North of the ecliptic.

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“…We also note that significant deceleration is required for the 15 April CME-driven shock to reach L1 with a speed of 422 km/s given a required, average velocity of 700 km/s, necessary to satisfy the time of flight to reach L1 at midnight 18 April. This is in contrast to the Tappin et al (2004) case study focusing on a May 2003 CME that was tracked using the Solar Mass Ejection Imager (SMEI); an "all sky" coronagraph. The results of this case study suggested the CME in question propagated from the Sun to 1 AU with an almost constant velocity of ∼900 km/s.…”

Section: Discussionmentioning

confidence: 96%

Transforming in-situ observations of CME-driven shock accelerated protons into the shock's reference frame.

Robinson

Simnett²

2005

Ann. Geophys.

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Abstract. We examine the solar energetic particle event following solar activity from 14, 15 April 2001 which includes a "bump-on-the-tail" in the proton energy spectra at 0.99 AU from the Sun. We find this population was generated by a CME-driven shock which arrived at 0.99 AU around midnight 18 April. As such this population represents an excellent opportunity to study in isolation, the effects of proton acceleration by the shock. The peak energy of the bump-onthe-tail evolves to progressively lower energies as the shock approaches the observing spacecraft at the inner Lagrange point. Focusing on the evolution of this peak energy we demonstrate a technique which transforms these in-situ spectral observations into a frame of reference co-moving with the shock whilst making allowance for the effects of pitch angle scattering and focusing. The results of this transform suggest the bump-on-the-tail population was not driven by the 15 April activity but was generated or at least modulated by a CME-driven shock which left the Sun on 14 April.

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Tracking a major interplanetary disturbance with SMEI

Cited by 59 publications

References 5 publications

V arc interplanetary coronal mass ejections observed with the Solar Mass Ejection Imager

V arc interplanetary coronal mass ejections observed with the Solar Mass Ejection Imager

SMEI direct, 3-D-reconstruction sky maps, and volumetric analyses, and their comparison with SOHO and STEREO observations

Transforming in-situ observations of CME-driven shock accelerated protons into the shock's reference frame.

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