Prediction of Coronal Mass Ejections from Vector Magnetograms

David Falconer

Abstract

We introduce two quantitative measures of the global nonpotentiality of predominantly bipolar active regions and explore their usefulness as indicators of whether an active region is likely to produce coronal mass ejections.  The two measures, length of strong-field strong-shear main neutral line (LSS) and global net current (IN), are obtained directly from vector magnetograms of the regions.  From   Marshall Space Flight Center vector magnetograms and Yohkoh Soft X-ray Telescope coronal X-ray images of four active regions, we (1) demonstrate that LSS and IN are each a useful indicator of an active regionís likely CME productivity, (2) find evidence that LSS and IN may be more reliable predictors of the CME productivity of active regions than is the presence or absence of sigmoidal structure in the X-ray images of the regions, and (3) suggest that there may be threshold values of LSS and IN above which CME production is likely and below which CME production is !unlikely.
 

  Organization: MSFC/UAH
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        e-mail: david.falconer@msfc.nasa.gov
       Address: David Falconer
   SD50
   NASA/MSFC
   Huntsville Al, 35824