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Proposal ID Chertok_163

Date of Proposal Apr 7 1998

firstname
Ilia

lastname
Chertok

institute
Institute of Terrestrial Magnetism, Ionosphere and Radio Wave
Propagation (IZMIRAN), Russian Academy of Sciences (IZMIRAN)

address
IZMIRAN, Troitsk, Moscow Region, 142092, Russia

email
ichertok@izmiran.troitsk.ru, ichertok@solar.stanford.edu

phone
(++7) (095) 334-0902

fax
(++7) (095) 334-0124

proposal
It is proposed to use the full-disk SOHO/EIT images, as well as
other relevant satellite and ground-based data to study large
scale (i.e. comparable with the solar disk diameter) shining
chains consisting from numerous bright blobs, points and threads.
At first these large-scale chains were found on the Nobeyama radio
heliograms at 17 GHz (Chertok and Shibasaki 1997,1998) due to
formation of modified images with a restricted range of the
brightness so that the most intense sources are suppressed and the
relatively weak features (such as the chains) become the most
pronounced.

The similar preliminary analysis of the modified SOHO/EIT (and
Yohkoh/SXT) images shows that the large-scale chains are still
more typical and pronounced in the EUV (and soft X-ray) ranges
than at microwaves. It reveals that rather often the bright
points are not scattered chaotically through the solar disc, but
are aligned at definite lines forming large-scale chains of
various (sometimes very strange) configurations. The reality of
these chains and threads is confirmed by the fact that in many
cases their form and location coincide on images belonging to
different ranges and types of observations (see Chertok 1997a).

The found microwave and EUV/X-ray chains mean that some
large-scale structures shine as a result of energy release
associated either with the long-term evolution of the large-scale
magnetic fields or with disturbances of extended magnetic fields
identified with CMEs. Apparently, the prolonged energy release,
occurring under such conditions initiates a plasma heating in the
wide temperature range (from tens of thousands to millions of
degrees), which takes place, on the one hand, in sufficiently
compact local elements corresponding to the individual bright
points, and, on the other hand, in some selected, globally
organized magnetic structures corresponding to the observed
large-scale chains.

It is planed to study the origin and evolution of these chains,
their relation to large scale magnetic fields, coronal holes,
CMEs, flares, as well as the features and dynamics of the blobs
and bright points forming these chains using various relevant
satellite and ground-based data.

Co-operation with Kiyoto Shibasaki is proposed.

The corresponding SOHO Guest Investigator proposal was submitted
and accepted by ESA (Chertok 1997b).

Chertok, I.M.: 1997a, Proc. of the Fifth SOHO Workshop, ESA
SP-404. P. 269.
Chertok, I.M.: 1997b, Some Manifestations of the Large-Scale
Solar Activity and their Relations to Coronal Mass Ejections.
A Proposal to the SOHO Guest Investigator Program.
Chertok, I.M. and Shibasaki, K.: 1997, Problems of the
Contemporary Radio Astronomy, XXVII Radio Astronomical Conference,
IAA, S.-Petersburg, V. 2. P. 76, (in Russian).
Chertok, I.M. and Shibasaki, K.: 1998, in preparation.

inside_collab
Work with Barabara Thompson is proposed.

consortium
no

topic
Large-Scale Structure

topic
Large-Scale Structure, CME

title
Large Scale Shining Chains on the Solar Disk

update added on 1998/08/16 at 06:20:38
Many working materials concerning the chains are gathered now at
the reconstructed web page
http://helios.izmiran.troitsk.ru/LARS/Chertok/

They include, in particular, the Nobeyama RH, Yohkoh/SXT,
SOHO/EIT events, as well as new TRACE images. Some brief
description and references on papers and reports are also given.

update added on 1999/02/05 at 03:15:15
An Interim Report of 5 February 1999

An analysis of many modified SOHO/EIT as well as TRACE, and
Yohkoh/SXT heliograms with a restrict range of intensities is
carried out basing on data from the existing SOHO Summary and
Synoptic Archives. It shows that the large-scale (comparable with
the solar disk diameter) shining chains, discovered before on the
Nobeyama Radioheliograph maps at 17 GHz, are also characteristic
of EUV, soft X-ray and other ranges.

Two the most important results of the present stage of the work
are as follows:

-- The detection of large-scale chains in microwave, EUV and soft
X-ray ranges and proof of their reality.

-- The preliminary analysis of some features of this novel
phenomenon, in particular, the strong evolution of the chains and
their association with CMEs.

An existence of the chains and threads appears to mean that some
large-scale structures light as a result of the reconnection and
energy release associated either with the long-term evolution of
the large-scale magnetic fields or with disturbances identified
with CME events. In particular, it is highly probable that the
detected chains and threads light quasi-separatrix layers forming
on the boundaries of different interacting large-scale magnetic
flux systems in the united, complex and global solar
magnetosphere.

Meanwhile, the work carried out should be considered only as some
introduction to more comprehensive studies of the large-scale
chains which should be done yet. This novel phenomenon looks very
interesting and could have not only helio physical, but also space
weather importance.


A list of publications

The following papers and abstracts concerning chains have been
published and submitted:

Chertok, I.M. Some Features of the Post-CME Energy Release in the
Solar Corona. Proc. of the Fifth SOHO Workshop, ESA SP-404. P. 269.
1997.

Chertok, I.M. and Shibasaki, K. Solar Large-Scale Bright
Structures in the Microwave Range by Observations with Nobeyama
Radioheliograph. Problems of the Contemporary Radio Astronomy.
XXVII Inter-Region Radio Astronomical Conf. V. 2. P. 76. 1997.

Chertok, I.M. Solar Large-Scale Chains of Bright Points After a
Coronal Mass Ejection of 22 August 1998. Bull. of the Russian
Academy of Sci., Phys. V 62. P. 1873. 1998.

Chertok, I.M. and Shibasaki, K. Microwave Large-Scale Shining
Chains and their Relation to CME/LDE Events. CESRA Workshop on
Coronal Explosive Events. Metsahovi Radio Observatory, Helsinki
University of Technology, Espoo, Finland. P. 29. 1998.

Chertok, I.M. Large-Scale Chains on the Solar Disk. New Cycle of
the Solar Activity: Observational and Theoretical Aspects.} Main
Astronomical Observatory, Russian Academy of Sciences. V. 2. P.
86. 1998.

Chertok, I.M. and Shibasaki, K. Solar Microwave Large-Scale Bright
Structures Observed with the Nobeyama Radioheliograph. Adv. Space
Res. 1998, in press. (The abstract has been published also in:
32nd Scientific Assembly of COSPAR. Abstracts. Nagoya, Japan, p.
351, 1998).

Chertok, I.M. Large-Scale Shining Chains in Solar Sources of
Geoeffective Events. VII Symp. on Solar-Terrestrial Physics of
Russia and CIS. Solar-Terrestrial Council of Russian Academy of
Sciences, Moscow, Russia. P. 47. 1998.

Chertok, I.M. and Shibasaki, K. Large-Scale Shining Chains on the
Solar Disk: Nobeyama Radioheliograph Data. Solar Physics with
Radio Observations, Proc. of Nobeyama Symp. 1998, NRO Report.
1998, in press. (The abstract has been published also in: Nobeyama
Symp. Abstract Book. NAOJ, Japan, p. 13, 1998).

Chertok, I.M. Large-Scale Shining Chains on the Solar Disk:
Yohkoh/SXT, SOHO/EIT and TRACE Data. Solar Physics with Radio
Observations, Proc. of Nobeyama Symp. 1998, NRO Report. 1998, in
press. (The abstract has been published also in: Nobeyama Symp.
Abstract Book. NAOJ, Japan, p. 14, 1998).

Materials for some further papers are being in preparation.


WWW Sites

A special WWW site on the large-scale chains with many data and
illustrations has been organized:
http://helios.izmiran.troitsk.ru/lars/Chertok/

Dr. Richard Harrison (PI of SOHO/CDS) has listed the large-scale
chain work as a linked project to the International
Solar Cycle Studies (ISCS) Working group 2 activities:
http://solg2.bnsc.rl.ac.uk/~harrison/iscs.html


Additional Proposals

The SOHO Guest Investigator Proposal No. NRA-97-08-OSS-385SOHO,
http://sohowww.nascom.nasa.gov/operations/guest_investigators/

The TRACE Analysis Project Proposal No. 220,
http://vestige.lmsal.com/cgi-bin/TRACE/reviewProposals.pl



Presented reports

The reports concerning the large-scale chains have been presented
at the following domestic and international meetings:

XXVII Inter-Region Radio Astronomical Conference, S.-Petersburg,
November 1997.

IV Congress of the Russian Astronomical Society, Moscow, November
1997.

Scientific Council of IZMIRAN, Troitsk, 20 January 1998.

XIV Russian Seminar on Solar Physics and Cosmic Electrodynamics,
Moscow, 10-11 March 1998.

Seminar of Astrophysical Institute Potsdam, Germany, 15 April
1998.

The CESRA Workshop on Coronal Explosive Events, Espoo, Finland,
9-13 June, 1998.

Conference on New Cycle of the Solar Activity: Observational and
Theoretical Aspects, S.-Petersburg, 24--29 June 1998.

The 32nd Scientific COSPAR Assembly. Section E2.2 on Coronal
Structure and Dynamics Near Solar Activity Minimum, Nagoya, Japan,
12-19 July 1998.

Nobeyama Symposium on Solar Physics with Radio Observations, 27-30
October 1998.

VII Symposium on Solar-Terrestrial Physics of Russia and CIS,
Troitsk, 15-18 December, 1998.



Abstracts Submitted at Forthcoming Meetings

Chertok, I.M. Detection of Solar Large-Scale Shining Chains and
their Relation to Coronal Mass Ejections. XXII IUGG General
Assembly, Workshop GA 4.01 Cycle 23 Solar Events and Heliospheric
Consequences, 18-30 July 1999, Birmingham, U.K.

Chertok, I.M. Solar Large-Scale Shining Chains: Two CME-Associated
Events. XXII IUGG General Assembly, Workshop GA 4.02 on CMEs,
Prominence Eruptions and Flare: Onsets and Relationships, 18-30
July 1999, Birmingham, U.K.

Chertok, I.M. SOHO/EIT and Other Data on Large-Scale Chains in the
Solar Atmosphere. 8th SOHO Workshop on Plasma Dynamics and
Diagnostics in the Solar Transition Region and Corona, 22--25 June
1999, Paris, France.








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