First Determination of 2D Speed Distribution within the Bodies of Coronal Mass Ejections. (arXiv:1905.11772v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ying_B/0/1/0/all/0/1">Beili Ying</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bemporad_A/0/1/0/all/0/1">Alessandro Bemporad</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giordano_S/0/1/0/all/0/1">Silvio Giordano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pagano_P/0/1/0/all/0/1">Paolo Pagano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feng_L/0/1/0/all/0/1">Li Feng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lu_L/0/1/0/all/0/1">Lei Lu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_H/0/1/0/all/0/1">Hui Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gan_W/0/1/0/all/0/1">Weiqun Gan</a>
The determination of the speed of Coronal Mass Ejections (CMEs) is usually
done by tracking brighter features (such as the CME front and core) in visible
light coronagraphic images and by deriving unidimensional profiles of the CME
speed as a function of altitude or time. Nevertheless, CMEs are usually
characterized by the presence of significant density inhomogeneities
propagating outward with different radial and latitudinal projected speeds,
resulting in a complex evolution eventually forming the Interplanetary CME. In
this work, we demonstrate for the first time how coronagraphic image sequences
can be analyzed to derive 2D maps of the almost instantaneous plasma speed
distribution within the body of CMEs. The technique is first tested with the
analysis of synthetic data, and then applied to real observations. Results from
this work allow to characterize the distribution and time evolution of kinetic
energy inside CMEs, as well as the mechanical energy (combined with the kinetic
and potential energy) partition between the core and front of the CME. In the
future, CMEs will be observed by two channels (VL and UV Ly-$alpha$)
coronagraphs, such as Metis on-board ESA Solar Orbiter mission as well as
Ly-$alpha$ Solar Telescope (LST) on-board Chinese Advanced Space-based Solar
Observatory (ASO-S) mission. Our results will help the analysis of these future
observations, helping in particular to take into account the 2D distribution of
Ly-$alpha$ Doppler dimming effect.
The determination of the speed of Coronal Mass Ejections (CMEs) is usually
done by tracking brighter features (such as the CME front and core) in visible
light coronagraphic images and by deriving unidimensional profiles of the CME
speed as a function of altitude or time. Nevertheless, CMEs are usually
characterized by the presence of significant density inhomogeneities
propagating outward with different radial and latitudinal projected speeds,
resulting in a complex evolution eventually forming the Interplanetary CME. In
this work, we demonstrate for the first time how coronagraphic image sequences
can be analyzed to derive 2D maps of the almost instantaneous plasma speed
distribution within the body of CMEs. The technique is first tested with the
analysis of synthetic data, and then applied to real observations. Results from
this work allow to characterize the distribution and time evolution of kinetic
energy inside CMEs, as well as the mechanical energy (combined with the kinetic
and potential energy) partition between the core and front of the CME. In the
future, CMEs will be observed by two channels (VL and UV Ly-$alpha$)
coronagraphs, such as Metis on-board ESA Solar Orbiter mission as well as
Ly-$alpha$ Solar Telescope (LST) on-board Chinese Advanced Space-based Solar
Observatory (ASO-S) mission. Our results will help the analysis of these future
observations, helping in particular to take into account the 2D distribution of
Ly-$alpha$ Doppler dimming effect.
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