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[17.02] Measuring Coronal Mass Ejection Masses from the Low through the Outer Corona

J.T. Burkepile (High Altitude Observatory/NCAR), F. Bagenal (U. Colorado, Boulder), J.A. Darnell, D. Elmore, T. Holzer, A.J. Hundhausen, A.L. Stanger (High Altitude Observatory/NCAR)

Estimates have been made of the masses contained in coronal mass ejections (CMEs) in the middle and outer corona [Howard et al. (1985), Howard et al. (1986) and Hundhausen et al. (1994)]. It is our goal to determine the flow of mass with height as the CME moves outward through the corona and to distinguish the outflow of material from brightenings due to deflections and compression created by the CMEs motion through the ambient coronal material. Coronal mass ejection measurements in the low corona are made using the Mauna Loa K-Coronameter. The K-Coronameter has recorded a few hundred CMEs that were also visible in the Solar Maximum Mission Coronagraph and in the Large Angle and Spectrometric Coronagraph experiment (LASCO) that image the middle and outer corona.

The mass of each CME is plotted as a function of height and compared with estimates for the amount of mass swept up by a CME moving with average speed through a typical coronal helmet streamer. For those events where the classic loop, cavity structure is apparent, the masses of the loop front and legs are recorded separately to better determine the amount of material propagating outward and the amount of material maintained in the legs following the passage of the CME.

The masses are combined with speeds of the CMEs to determine the kinetic energy of the CME as a function of height. As an example we report on a CME which occurred on September 9, 1997 and appeared over the northwest limb in both the MK3 and LASCO data. The mass of the CME appeared to increase from 1.5x10¹⁵ grams in the MK3 field to 6.2x10¹⁵ grams in the LASCO field of view. The CME was continuing to accelerate and the kinetic energy increased by an order of magnitude from the low corona value of 2.5x10³⁰ ergs in MK3 to 2.0x10³¹ ergs in the LASCO field of view.

References: Howard, R.A., N.R. Sheeley, Jr., M.J. Koomen, and D.J. Michels, 'Coronal Mass Ejections: 1979-1981', (1985), J. Geophys. Res., 90, 8173-8191 Howard, R.A., N.R. Sheeley, Jr., D.J. Michels, M.J. Koomen, ' The Solar Cycle Dependence of Coronal Mass Ejections', (1986) in: The Sun and the Heliosphere in Three Dimensions, Marsden, R.G. (ed)., 1986, p 107-111

Hundhausen, A.J., A.L. Stanger, and S.A. Serbicki,'Mass and Energy Contents of Coronal Mass Ejections: SMM Results from 1980 and 1984-1988.', (1994) in: Proc. of the Third SOHO Workshop, Estes Park Colorado, p 409.

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