The Calm before the Storm: The Link between Quiescent Cavities and Coronal Mass Ejections

By S. Gibson, J. Burkepile, G. Toma, A. Stanger. Astrophysical Journal, 2006

158 citations recorded by the source corpus.

Determining the state of the corona prior to CMEs is crucial to understanding and ultimately predicting solar eruptions. A common and compelling feature of CMEs is their three-part morphology, as seen in white-light observations of a bright expanding loop, followed by a relatively dark cavity, and finally a bright core associated with an erupting prominence/filament. This morphology is an important constraint on CME models. It is also quite common for a three-part structure of loop, cavity, and prominence core to exist quiescently in the corona, and this is equivalently an important constraint on models of CME-precursor magnetic structure. These quiescent structures exist in the low corona, primarily below approximately 1.6 R☉, and so are currently observable in white light during solar eclipses, or else by the Mauna Loa Solar Observatory Mk4 coronameter. We present the first comprehensive, quantitative analysis of white-light quiescent cavities as observed by the Mk4 coronameter. We find that such cavities are ubiquitous, as they are the coronal limb counterparts to filament channels observed on the solar disk. We consider examples that range from extremely long-lived, longitudinally extended polar-crown-filament-related cavities to smaller cavities associated with filaments near or within active regions. The former are often visible for days and even weeks at a time and can be identified as long-lived cavities that survive for months. We quantify cavity morphology and intensity contrast properties and consider correlations between these properties. We find multiple cases in which quiescent cavities directly erupt into CMEs and consider how morphological and intensity contrast properties of these cases differ from the general population of cavities. Finally, we discuss the implications that these observations may have for the state of the corona just prior to a CME, and more generally for the nature of coronal MHD equilibria.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/9bdb4b29a444b166eb4ef64d1057b7d89fa31155

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In Astronomy and Astrophysics

1. A. Vourlidas
2. S. Gibson
3. S. Patsourakos
4. J. Zhang
5. Yuhong Fan
6. R. Howard
7. Xin Cheng
8. M. Ding

Citations in the corpus

• OBSERVING FLUX ROPE FORMATION DURING THE IMPULSIVE PHASE OF A SOLAR ERUPTION (2011, background): “The existence of a flux rope could explain the dark cavity structure of a CME (e.g., Gibson et al. 2006; Wang & Stenborg 2010).”
• DIFFERENTIAL EMISSION MEASURE ANALYSIS OF MULTIPLE STRUCTURAL COMPONENTS OF CORONAL MASS EJECTIONS IN THE INNER CORONA (2012, methodology): “…axis, is often used to interpret the three-part structure of a CME; for instance, the dark cavity and the bright core of the CME correspond to the whole flux rope and the magnetic dips of the flux rope, respectively (e.g., Low & Hundhausen 1995; Chen 1996; Gibson et al. 2006; Riley et al. 2008).”
• Coronal prominence structure and dynamics: A magnetic flux rope interpretation (2006, background): “[14] White light coronagraph observations often show a cavity, which may surround a prominence, both in a quiescent state prior to an eruption (Figure 3a) and as an aspect of CMEs (Figures 8a–8d) [Gibson et al., 2006b, and references therein].”
• How Many CMEs Have Flux Ropes? Deciphering the Signatures of Shocks, Flux Ropes, and Prominences in Coronagraph Observations of CMEs (2012, background): “While these concepts are widely accepted thanks to the extensive observations of quiescent cavities and prominences (Gibson et al., 2006), there seems to be a lingering confusion on the location and importance of the prominence relative to the erupting FR or cavity.”
• NO TRACE LEFT BEHIND: STEREO OBSERVATION OF A CORONAL MASS EJECTION WITHOUT LOW CORONAL SIGNATURES (2009, methodology): “To compare the sizes, we measured the widths of both cavities, similarly to Gibson et al. (2006).”
• DIRECT EVIDENCE FOR A FAST CORONAL MASS EJECTION DRIVEN BY THE PRIOR FORMATION AND SUBSEQUENT DESTABILIZATION OF A MAGNETIC FLUX ROPE (2012, background): “…(SXRs), has shown large-scale quiescent cavities going through a quasi-static rise phase, with a duration of up to several days, which could eventually erupt giving rise to CMEs (e.g., Engvold 1989; Hudson et al. 1999; Koutchmy et al. 2004; Gibson et al. 2006; Su et al. 2010; Régnier et al. 2011).”
• Properties of Ground Level Enhancement Events and the Associated Solar Eruptions During Solar Cycle 23 (2012, unknown): “Gibson et al. (2006) studied a number of cavities observed by the Mauna Loa K-coronameter, whose heights ranged from 1.25 to 1.6 Rs .”