Large-scale magnetic structures of coronal mass ejections

2002 ◽  
Vol 45 (S1) ◽  
pp. 57-64 ◽  
Author(s):  
Jingxiu Wang ◽  
Jun Zhang ◽  
Yuanyong Deng ◽  
Jingqun Li ◽  
Lirong Tian ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Large Scale ◽  
Magnetic Structures

LASCO Observations of Disconnected Magnetic Structures Out to Beyond 28 Solar Radii During Coronal Mass Ejections

1997 ◽  
pp. 685-698
Author(s):  
G. M. Simnett ◽  
S. J. Tappin ◽  
S. P. Plunkett ◽  
D. K. Bedford ◽  
C. J. Eyles ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Magnetic Structures

scholarly journals Experimental Study of the Orientation of Magnetic Fields in the Corona

1971 ◽  
Vol 43 ◽  
pp. 580-587 ◽  
Author(s):  
P. Charvin
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Magnetic Fields ◽  
Large Scale ◽  
Coronal Line ◽  
Magnetic Structures ◽  
Polarization Measurements ◽  
First Results

We present polarization measurements obtained in 1970 in the green coronal line with a new coronameter located at the Pic du Midi. The analysis of these data has been conducted with the theory given by the writer in 1964 and 1965. It appears that magnetic field orientations in the Corona can be deduced from the above measurements. First results showing large scale magnetic structures are presented.

scholarly journals Dynamo in Astrophysics

1990 ◽  
Vol 140 ◽  
pp. 83-89
Author(s):  
A.A. Ruzmaikin
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Turbulent Flow ◽  
Large Scale ◽  
Spiral Galaxies ◽  
Clusters Of Galaxies ◽  
Magnetic Structures ◽  
Random Magnetic Field ◽  
Astrophysical Objects

The fast dynamo acting in a turbulent flow explains the origin of magnetic fields in astrophysical objects. Stellar cycles and large-scale magnetic fields in spiral galaxies reflect the behaviour of a mean magnetic field. Intermittent magnetic structures in clusters of galaxies are associated with random magnetic field.

scholarly journals Why are CMEs large-scale coronal events: nature or nurture?

2008 ◽  
Vol 26 (10) ◽  
pp. 3077-3088 ◽  
Author(s):  
L. van Driel-Gesztelyi ◽  
G. D. R. Attrill ◽  
P. Démoulin ◽  
C. H. Mandrini ◽  
L. K. Harra
Keyword(s):  
Magnetic Reconnection ◽  
Large Scale ◽  
Observational Evidence ◽  
Angular Width ◽  
Small Scale ◽  
Apparent Contradiction ◽  
Lower Corona ◽  
Magnetic Structures ◽  
Source Regions ◽  
Scale Response

Abstract. The apparent contradiction between small-scale source regions of, and large-scale coronal response to, coronal mass ejections (CMEs) has been a long-standing puzzle. For some, CMEs are considered to be inherently large-scale events – eruptions in which a number of flux systems participate in an unspecified manner, while others consider magnetic reconnection in special global topologies to be responsible for the large-scale response of the lower corona to CME events. Some of these ideas may indeed be correct in specific cases. However, what is the key element which makes CMEs large-scale? Observations show that the extent of the coronal disturbance matches the angular width of the CME – an important clue, which does not feature strongly in any of the above suggestions. We review observational evidence for the large-scale nature of CME source regions and find them lacking. Then we compare different ideas regarding how CMEs evolve to become large-scale. The large-scale magnetic topology plays an important role in this process. There is amounting evidence, however, that the key process is magnetic reconnection between the CME and other magnetic structures. We outline a CME evolution model, which is able to account for all the key observational signatures of large-scale CMEs and presents a clear picture how large portions of the Sun become constituents of the CME. In this model reconnection is driven by the expansion of the CME core resulting from an over-pressure relative to the pressure in the CME's surroundings. This implies that the extent of the lower coronal signatures match the final angular width of the CME.

scholarly journals The Large-Scale Source Regions of Coronal Mass Ejections

2004 ◽  
Vol 2004 (IAUS226) ◽  
pp. 200-205 ◽  
Author(s):  
Guiping Zhou ◽  
Jingxiu Wang ◽  
Jun Zhang ◽  
Chijie Xiao
Keyword(s):  
Coronal Mass Ejections ◽  
Large Scale ◽  
Source Regions

scholarly journals Beyond sunspots: Studies using the McIntosh Archive of global solar magnetic field patterns

2016 ◽  
Vol 12 (S328) ◽  
pp. 93-100 ◽  
Author(s):  
Sarah E. Gibson ◽  
David Webb ◽  
Ian M. Hewins ◽  
Robert H. McFadden ◽  
Barbara A. Emery ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Solar Magnetic Field ◽  
Coronal Holes ◽  
Magnetic Polarity ◽  
Solar Cycles ◽  
Polarity Inversion ◽  
Magnetic Structures ◽  
Field Patterns ◽  
Global Evolution

AbstractIn 1964 (Solar Cycle 20; SC 20), Patrick McIntosh began creating hand-drawn synoptic maps of solar magnetic features, based on Hα images. These synoptic maps were unique in that they traced magnetic polarity inversion lines, and connected widely separated filaments, fibril patterns, and plage corridors to reveal the large-scale organization of the solar magnetic field. Coronal hole boundaries were later added to the maps, which were produced, more or less continuously, into 2009 (i.e., the start of SC 24). The result was a record of ~45 years (~570 Carrington rotations), or nearly four complete solar cycles of synoptic maps. We are currently scanning, digitizing and archiving these maps, with the final, searchable versions publicly available at NOAA's National Centers for Environmental Information. In this paper we present preliminary scientific studies using the archived maps from SC 23. We show the global evolution of closed magnetic structures (e.g., sunspots, plage, and filaments) in relation to open magnetic structures (e.g., coronal holes), and examine how both relate to the shifting patterns of large-scale positive and negative polarity regions.

scholarly journals VLBI for probing large-scale magnetic structures of stars

1996 ◽  
Vol 176 ◽  
pp. 173-180
Author(s):  
J.-F. Lestrade
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Large Scale ◽  
Electron Acceleration ◽  
High Gravity ◽  
Magnetic Structures

By VLBI astrometry, we show that the two RSCVn type binaries, UX Ari and σ2 CrB, have a preferred site of radio emission which is the intra-system region. It is known that radio emission from these stars is from the gyro-synchrotron process associated with large-scale magnetic fields. High gravity in the intra-system region might favor dense magnetic loops. Interactions in this region between loops attached to the surfaces of the two stellar components might produce reconnections required for electron acceleration.

scholarly journals Active Longitudinal Structures of the Sun from MDI and EIT Observations

2001 ◽  
Vol 203 ◽  
pp. 251-253
Author(s):  
E. E. Benevolenskaya ◽  
A. G. Kosovichev ◽  
P. H. Scherrer
Keyword(s):  
Large Scale ◽  
Transition Period ◽  
Spectral Lines ◽  
Solar Interior ◽  
Solar Cycles ◽  
Magnetic Structures ◽  
Rotation Rates ◽  
Large Scale Magnetic Field ◽  
Current Cycle ◽  
Longitudinal Structures

We present results of investigation of the large-scale structure of the solar corona during the transition period between solar cycles 22 and 23 and at the beginning of the current cycle 23 using the SOHO/EIT EUV data obtained in 171 Å, 195 Å, 284 Å and 304 Å lines. For this analysis the data were transformed into synoptic maps for each of the spectral lines, and for the 195/171 line ratio which is an index of the coronal temperature. The synoptic maps reveal stable longitudinal structures in the coronal intensities and temperature, which are related to large-scale magnetic field structures. We discuss the relation between the coronal and photospheric magnetic structures obtained from the SOHO/MDI data, and compare the rotation rates of these structures with the rotation profile of the solar interior in order to determine the possible origin of the coronal structures.

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