Automated LASCO CME catalog for solar cycle 23: are CMEs scale invariant - AstrophysicsReport as inadecuate

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Abstract: In this paper we present the first automatically constructed LASCO CMEcatalog, a result of the application of the Computer Aided CME Trackingsoftware CACTus on the LASCO archive during the interval September 1997 -January 2007. We have studied the CME characteristics and have compared themwith similar results obtained by manual detection CDAW CME catalog. Onaverage CACTus detects less than 2 events per day during solar minimum up to 8events during maximum, nearly half of them being narrow < 20 degrees.Assuming a correction factor, we find that the CACTus CME rate is surprisinglyconsistent with CME rates found during the past 30 years. The CACTus statisticsshow that small scale outflow is ubiquitously observed in the outer corona. Themajority of CACTus-only events are narrow transients related to previous CMEactivity or to intensity variations in the slow solar wind, reflecting itsturbulent nature. A significant fraction about 15% of CACTus-{\it only}events were identified as independent events, thus not related to other CMEactivity. The CACTus CME width distribution is essentially scale invariant inangular span over a range of scales from 20 to 120 degrees while previouscatalogues present a broad maximum around 30 degrees. The possibility that thesize of coronal mass outflows follow a power law distribution could indicatethat no typical CME size exists, i.e. that the narrow transients are notdifferent from the larger well-defined CMEs.

Author: E. Robbrecht, D. Berghmans, R.A.M. Van der Linden


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