A Challenging Solar Eruptive Event of 18 November 2003 and the Causes of the 20 November Geomagnetic Superstorm. III. Catastrophe of the Eruptive Filament at a Magnetic Null Point and Formation of an Opposite-Handedness CME

Our analysis in Papers I and II (Grechnev et al. , Solar Phys. 289 , 289, 2014b and Solar Phys. 289 , 1279, 2014c ) of the 18 November 2003 solar event responsible for the 20 November geomagnetic superstorm has revealed a complex chain of eruptions. In particular, the eruptive filament encountered a...

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Bibliographic Details
Published in:Solar physics 2014-10, Vol.289 (10), p.3747-3772
Main Authors: Uralov, A. M., Grechnev, V. V., Rudenko, G. V., Myshyakov, I. I., Chertok, I. M., Filippov, B. P., Slemzin, V. A.
Format: Article
Language:English
Subjects:
Astrophysics and Astroparticles
Atmospheric Sciences
Bifurcations
Chains
Corona
Coronal mass ejection
Filaments
Geomagnetism
Helicity
Magnetic clouds
Magnetic fields
Physics
Physics and Astronomy
Solar flares
Solar physics
Space Exploration and Astronautics
Space Sciences (including Extraterrestrial Physics
Sun
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Summary:Our analysis in Papers I and II (Grechnev et al. , Solar Phys. 289 , 289, 2014b and Solar Phys. 289 , 1279, 2014c ) of the 18 November 2003 solar event responsible for the 20 November geomagnetic superstorm has revealed a complex chain of eruptions. In particular, the eruptive filament encountered a topological discontinuity located near the solar disk center at a height of about 100 Mm, bifurcated, and transformed into a large cloud, which did not leave the Sun. Concurrently, an additional CME presumably erupted close to the bifurcation region. The conjectures about the responsibility of this compact CME for the superstorm and its disconnection from the Sun are confirmed in Paper IV (Grechnev et al. , Solar Phys. submitted, 2014a ), which concludes about its probable spheromak-like structure. The present article confirms the presence of a magnetic null point near the bifurcation region and addresses the origin of the magnetic helicity of the interplanetary magnetic clouds and their connection to the Sun. We find that the orientation of a magnetic dipole constituted by dimmed regions with the opposite magnetic polarities away from the parent active region corresponded to the direction of the axial field in the magnetic cloud, while the pre-eruptive filament mismatched it. To combine all of the listed findings, we propose an intrinsically three-dimensional scheme, in which a spheromak-like eruption originates via the interaction of the initially unconnected magnetic fluxes of the eruptive filament and pre-existing ones in the corona. Through a chain of magnetic reconnections their positive mutual helicity was transformed into the self-helicity of the spheromak-like magnetic cloud.
ISSN:0038-0938
1573-093X
DOI:10.1007/s11207-014-0536-4