Solar Large-Scale Chains: Some
Associated with Halo Coronal
IZMIRAN, Troitsk, Moscow Region, 142190,
Relatively weak extended emitting chains
with a characteristic length comparable with the solar disk diameter were
detected on the modified heliograms in the microwave (Nobeyama Radioheliograph),
soft X-ray (Yohkoh/SXT), EUV (SOHO/EIT, TRACE), and other ranges (Chertok,
1997…2000, Chertok and Shibasaki, 1999, 2000).
The chains appear to light up separators
or quasi-separatrix layers between different interacting large-scale
magnetic flux systems in the global solar magnetosphere and, in
particular, to outline large-scale coronal structures involved in the CME
(For active regions:
Somov, 1992; D\'emoulin et al., 1996; Priest, 1996; Sakurai and Wang, 1999;
Some features of the chains and their relations
to CMEs are illustrated for a number of halo CME-associated events.
23 events of 1997-2000
SOHO/EIT (Delaboudinière et al., 1995)
images and movies at 171 and 195 ;
Yohkoh/SXT (Tsuneta et al., 1991) images
H-alpha heliograms of BBSO and Meudon;
SOHO/LASCO (Brueckner et al., 1995)
images and movies
SOHO/EIT, Yohkoh/SXT -- negative (inverted) images;
H-alpha, SOHO/LASCO -- positive (normal) images.
-- Javaskript movies from modified SOHO/EIT images at 195 A
Halo-CME-associated events of November 1997
3, 1997 : 09-10 UT,
S20 W15, 1B/M4.2 flare preceding the proton events
4, 1997 : 05:58 UT, S14 W33,
2B/X2.1 flare; ISTP event; J(E>10 MeV)~72 pfu;
FD~3%; Dst~-110 nT
6, 1997 : 11:55 UT,
S18 W63, 2B/X9.4 flare; ISTP event; J(E>10 MeV)~490 pfu;
The analysis confirms the previous assumptions
and conclusions concerning the evolution of the chains in the global solar
magnetosphere and their relations to CMEs.
It is obvious that the chains connect all
remote active regions and centers, including ones located in different
solar hemispheres on the both sides from the helioequator. It means that
the global solar magnetosphere exists really.
The features of the chain appear to support
the assumption that the chains can particularly light up separators
and quasi-separatrix layers, forming on the boundaries
of different interacting and reconnecting large-scale magnetic flux systems.
the chains can be considered as an indicator of the evolution of the global
The chains demonstrate clearly that the
flares and/or filament eruptions, which are considered usually as sources
of the corresponding CMEs, indeed are only a part of a much more large-scale
(or even global) activity covering often the whole solar disk.
The significant chain evolution takes place
usually during many hours both before and after a CME eruption.
The chains preceding CMEs appear to display
energy release resulting from evolving large-scale magnetic structures
at the stage when the development of these structures approach to a CME
The chains following CMEs can result from
the post-eruption energy release when magnetic fields in an extended region
of the corona, strongly disturbed by a CME eruption, relaxes to its initial
state via magnetic reconnection in large-scale coronal current sheets.
Generally, the chains appear to outline
the large-scale coronal structures involved in the processes of the CME
eruption and post-eruption energy release.
More information and data on the solar
large-scale chains are presented at the web page: