QUANTITATIVE MEASUREMENTS OF CORONAL MASS EJECTION-DRIVEN SHOCKS FROM LASCO OBSERVATIONS

By V. Ontiveros, A. Vourlidas. 2008

160 citations recorded by the source corpus.

In this paper, we demonstrate that coronal mass ejection (CME)-driven shocks can be detected in white light coronagraph images and in which properties such as the density compression ratio and shock direction can be measured. Also, their propagation direction can be deduced via simple modeling. We focused on CMEs during the ascending phase of solar cycle 23 when the large-scale morphology of the corona was simple. We selected events which were good candidates to drive a shock due to their high speeds (V > 1500 km s−1). The final list includes 15 CMEs. For each event, we calibrated the LASCO data, constructed excess mass images, and searched for indications of faint and relatively sharp fronts ahead of the bright CME front. We found such signatures in 86% (13/15) of the events and measured the upstream/downstream densities to estimate the shock strength. Our values are in agreement with theoretical expectations and show good correlations with the CME kinetic energy and momentum. Finally, we used a simple forward modeling technique to estimate the three-dimensional shape and orientation of the white light shock features. We found excellent agreement with the observed density profiles and the locations of the CME source regions. Our results strongly suggest that the observed brightness enhancements result from density enhancements due to a bow-shock structure driven by the CME.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5f4b5c2cb029f3e6d9ba0e7df5b26fbc876b4c26

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In Astronomy and Astrophysics

1. M. Temmer
2. H. Hudson
3. T. Howard
4. D. Webb
5. A. Vourlidas
6. Nat Gopalswamy
7. R. Howard
8. Wei Liu

Citations in the corpus

• THE LONGITUDINAL PROPERTIES OF A SOLAR ENERGETIC PARTICLE EVENT INVESTIGATED USING MODERN SOLAR IMAGING (2011, unknown): “The existence of white-light signatures of CME-driven shocks was investigated further by Manchester et al. (2008) and Ontiveros & Vourlidas (2009).”
• An Observational Overview of Solar Flares (2011, background): “Indeed, the coronagraphic observations show image evidence, in many cases, for CME-driven shocks in the middle corona (Vourlidas et al. 2003; Ontiveros & Vourlidas 2009).”
• Solar Orbiter (2012, background): “Recent studies of LASCO images obtained during the rising phase of Solar Cycle 23 have demonstrated the feasibility of detecting CME-driven shocks from a few to ∼20 RSun and of measuring their density compression ratio and propagation direction (Vourlidas et al., 2003; Ontiveros and Vourlidas, 2009)”
• OBSERVATIONS AND INTERPRETATION OF A LOW CORONAL SHOCK WAVE OBSERVED IN THE EUV BY THE SDO/AIA (2011, background): “Coronal shocks have been identified from white light coronagraph images by morphology and density enhancement (e.g., Vourlidas et al. 2003; Ontiveros & Vourlidas 2009) and from UV spectra (Raymond et al. 2000; Mancuso & Bemporad 2009) by measuring oxygen kinetic temperatures.”
• Coronal Mass Ejections: Observations (2012, background): “Sharp, bright rims ahead of fast CMEs occasionally observed by LASCO are now considered by some to be evidence of shocks (e.g., Vourlidas et al., 2003; Ontiveros and Vourlidas, 2009; Vourlidas and Ontiveros, 2009).”
• Space weather: the solar perspective (2021, background): “…manifestations of shock and driver could be well confirmed and it is now well acknowledged that the outer envelope of the observed CME presents the expanding shock or compressed shell that encompasses the driver (e.g., Ciaravella et al. 2006; Ontiveros and Vourlidas 2009; Vourlidas et al. 2013).”
• How Many CMEs Have Flux Ropes? Deciphering the Signatures of Shocks, Flux Ropes, and Prominences in Coronagraph Observations of CMEs (2012, background): “The, albeit few, 3D reconstructions of the density profile across the front (Ontiveros and Vourlidas, 2009) can readily explaining the profile as a result of LOS integration and recover compression ratios in agreement with theoretical expectations (less than 4).”