Quantifying the Propagation of Fast Coronal Mass Ejections from the Sun to Interplanetary Space Combining Remote Sensing and Multi-Point in-situ Observations. (arXiv:1908.04450v1 [astro-ph.SR])

Quantifying the Propagation of Fast Coronal Mass Ejections from the Sun to Interplanetary Space Combining Remote Sensing and Multi-Point in-situ Observations. (arXiv:1908.04450v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zhao_X/0/1/0/all/0/1">Xiaowei Zhao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_Y/0/1/0/all/0/1">Ying D. Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_H/0/1/0/all/0/1">Huidong Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_R/0/1/0/all/0/1">Rui Wang</a>

In order to have a comprehensive view of the propagation and evolution of
coronal mass ejections (CMEs) from the Sun to deep interplanetary space beyond
1 au, we carry out a kinematic analysis of 7 CMEs in solar cycle 23. The events
are required to have coordinated coronagraph observations, interplanetary type
II radio bursts, and multi-point in-situ measurements at the Earth and Ulysses.
A graduated cylindrical shell model, an analytical model without free
parameters and a magnetohydrodynamic model are used to derive CME kinematics
near the Sun, to quantify the CME/shock propagation in the Sun-Earth space, and
to connect in-situ signatures at the Earth and Ulysses, respectively. We find
that each of the 7 CME-driven shocks experienced a major deceleration before
reaching 1 au and thereafter propagated with a gradual deceleration from the
Earth to larger distances. The resulting CME/shock propagation profile for each
case is roughly consistent with all the data, which verifies the usefulness of
the simple analytical model for CME/shock propagation in the heliosphere. The
statistical analysis of CME kinematics indicates a tendency that the faster the
CME, the larger the deceleration, and the shorter the deceleration time period
within 1 au. For several of these events, the associated geomagnetic storms
were mainly caused by the southward magnetic fields in the sheath region. In
particular, the interaction between a CME-driven shock and a preceding ejecta
significantly enhanced the preexisting southward magnetic fields and gave rise
to a severe complex geomagnetic storm.

In order to have a comprehensive view of the propagation and evolution of
coronal mass ejections (CMEs) from the Sun to deep interplanetary space beyond
1 au, we carry out a kinematic analysis of 7 CMEs in solar cycle 23. The events
are required to have coordinated coronagraph observations, interplanetary type
II radio bursts, and multi-point in-situ measurements at the Earth and Ulysses.
A graduated cylindrical shell model, an analytical model without free
parameters and a magnetohydrodynamic model are used to derive CME kinematics
near the Sun, to quantify the CME/shock propagation in the Sun-Earth space, and
to connect in-situ signatures at the Earth and Ulysses, respectively. We find
that each of the 7 CME-driven shocks experienced a major deceleration before
reaching 1 au and thereafter propagated with a gradual deceleration from the
Earth to larger distances. The resulting CME/shock propagation profile for each
case is roughly consistent with all the data, which verifies the usefulness of
the simple analytical model for CME/shock propagation in the heliosphere. The
statistical analysis of CME kinematics indicates a tendency that the faster the
CME, the larger the deceleration, and the shorter the deceleration time period
within 1 au. For several of these events, the associated geomagnetic storms
were mainly caused by the southward magnetic fields in the sheath region. In
particular, the interaction between a CME-driven shock and a preceding ejecta
significantly enhanced the preexisting southward magnetic fields and gave rise
to a severe complex geomagnetic storm.

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