Abstract.
We present a study comparing the energy carried away by a coronal
mass ejection (CME) and the radiative energy loss in associated flare
plasma, with
the decrease in magnetic free energy during a release in active region
NOAA 10930
on December 13, 2006 during the declining phase of the solar cycle 23.
The ejected
CME was fast and directed towards the Earth with a projected speed of
~1780 km s-1
and a de-projected speed of ~3060 km s-1. We regard these as lower and
upper
limits for our calculations. It was accompanied by an X3.4 class flare
in the active
region. The CME carried (1.2-4.5)X1032 erg (projected-deprojected) of
kinetic and
gravitational potential energy. The estimated radiative energy loss
during the flare
was found to be 9.04X1030 erg. The sum of these energies was compared
with the
decrease in measured free magnetic energy during the flare/CME. The free
energy is
that above the minimum energy configuration and was estimated using the
magnetic
virial theorem. The estimated decrease in magnetic free energy is large,
3.11X1032 erg
after the flare/CME compared to the pre-flare energy. Given the range of
possible
energies we estimate that 50-100% of the CME energy arose from the
active region.
The rest of the free magnetic energy was distributed among the radiative
energy loss,
particle acceleration, plasma and magnetic field reorientation.
Keywords : Sun: activity - Sun: magnetic fields - Sun: coronal mass
ejections