Catalogue of MLSO/MK4 White Light Cavities

Determining the state of the corona prior to coronal mass ejections (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 lastly a bright core associated with an erupting prominence/filament.

Here is a catalogue providing detailed analysis of 98 white light cavities observed by MLSO's Mk4 coronameter:

Steve Tomczyk

Dr. Steven Tomczyk is a Senior Scientist and Section Head in the High Altitude Observatory at the National Center for Atmospheric Research. He has spent his career developing instrumentation for the remote sensing of magnetic and velocity fields on the Sun. 

Solar Maximum Mission Information and Data on the MLSO website

The Solar Maximum Mission (SMM) satellite was launched in 1980 aboard a NASA Delta rocket. Among SMM's primary science objectives was the study of the dynamics of solar flares and the study of solar magnetic fields associated with the flare phenomenon. Towards this end, the High Altitude Observatory (HAO) provided a white-light coronagraph/polarimeter (C/P) to study the relationship of the corona to the flare process.

Mk4-STEREO-LASCO Composites

HAO / MLSO is now providing daily composite images of the solar corona as seen from 3 viewing angles: STEREO B, Earth-Sun, and STEREO-A. The STEREO A/B composites consist of SECCHI images from: EUVI (inner corona seen against the solar disk), the MLSO MK4 K-Coronameter (blue), the COR1 Coronagraph (green) and the COR2 Coronagraph (in red). The SOHO/MK4 composite combines EIT (solar disk), MK4 (blue) and LASCO C2 (red). MK4 images are NOT rotated to match the STEREO viewing angles.

Full Res Mk4 Images & Movies Available

The home page of this MLSO website now features full-resolution GIF images and movies for the Mk4 instrument. Clicking on the thumbnail images for this instrument will now give you higher resolution GIF images of the latest data.

Mk4 Composites

COronal Multi-channel Polarimeter

The CoMP instrument (see Tomczyk, et al. 2008) can observe the coronal magnetic field with a full FOV in the low corona (~1.03 to 1.5 Rsun), as well as obtain information about the plasma density and motion. Like Solar-C, CoMP records the intensity and the linear and circular polarization (Stokes I,Q,U,V) of the forbidden lines of Fe XIII at 1074.7 nm and also at 1079.8 nm.


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