Editorial: The Magnetic Structures and Their Role in The Evolution of Coronal Mass Ejections

We review some recent studies of mass ejections from the Sun using 2-D imaging observations of the Clark Lake multifrequency radioheliograph. Radio signatures of both fast and slow coronal mass ejections (CMEs) have been observed using the Clark Lake radioheliograph. Using temporal and positional analysis of moving type IV and type II bursts, and white light CMEs we find that the type II's and CMEs need not have a direct cause and effect relationship. Instead, the type II seems to be generated by a “decoupled shock”, probably due to an associated flare. The moving type IV burst requires nonthermal particles trapped in magnetic structures associated with the CME. Since nonthermal particles can be generated independent of the speed of CMEs, moving type IV bursts need not be associated only with fast CMEs. Specific examples are presented to support these views.

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Large-scale magnetic structures of coronal mass ejections

Science in China Series A Mathematics ◽

10.1007/bf02889685 ◽

2002 ◽

Vol 45 (S1) ◽

pp. 57-64 ◽

Cited By ~ 3

Author(s):

Jingxiu Wang ◽

Jun Zhang ◽

Yuanyong Deng ◽

Jingqun Li ◽

Lirong Tian ◽

...

Keyword(s):

Coronal Mass Ejections ◽

Large Scale ◽

Magnetic Structures

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Utilizing galactic cosmic rays as signatures of coronal mass ejections

10.5194/egusphere-egu21-463 ◽

2021 ◽

Author(s):

Mateja Dumbovic

Keyword(s):

Coronal Mass Ejections ◽

Interplanetary Space ◽

Flux Rope ◽

Forbush Decrease ◽

Cosmic Ray ◽

Galactic Cosmic Rays ◽

Forbush Decreases ◽

Magnetic Structures ◽

Different Types ◽

Galactic Cosmic Ray

<p>Coronal mass ejections (CMEs) are the most violent eruptions in the solar system. They are one of the main drivers of the heliospheric variability and cause various interplanetary as well as planetary disturbances. One of their very common in-situ signatures are short-term reductions in the galactic cosmic ray (GCR) flux (i.e. Forbush decreases), which are measured by ground-based instruments at Earth and Mars, as well as various spacecraft throughout the heliosphere (most recently by Solar Orbiter). In general, interplanetary magnetic structures interact with GCRs producing depressions in the GCR flux. Therefore, different types of interplanetary magnetic structures cause different types of GCR depressions, allowing us to distinguish between them. In the interplanetary space the CME typically consists of two structures: the presumably closed flux rope and the shock/sheath which is formed ahead of the flux rope as it propagates and expands in the interplanetary space. Interaction of GCRs with these two structures is modelled separately, where the flux-rope related Forbush decrease can be modelled assuming that the GCRs diffuse slowly into the expanding flux rope, which is initially empty at its center (ForbMod model). The resulting Forbush decrease at a given time, i.e. heliospheric distance, reflects the evolutionary properties of CMEs. However, ForbMod is not yet able to take into account complex, non-self-similar evolution of the flux rope. Nevertheless, Forbush decreases can undoubtedly give us information on the CMEs in the heliosphere, especially where other measurements are lacking, and with further development, Forbush decrease reverse modelling could provide insight into the CME evolution.</p>

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A numerical study of two interacting coronal mass ejections

Annales Geophysicae ◽

10.5194/angeo-22-2245-2004 ◽

2004 ◽

Vol 22 (6) ◽

pp. 2245-2254 ◽

Cited By ~ 40

Author(s):

J. M. Schmidt ◽

P. J. Cargill

Keyword(s):

Magnetic Reconnection ◽

Coronal Mass Ejections ◽

Numerical Study ◽

Large Population ◽

Magnetic Interaction ◽

Magnetic Structures ◽

Seed Particles ◽

Seed Population ◽

Forward Shock ◽

Single Structure

Abstract. The interaction in the solar wind between two coronal mass ejections (CMEs) is investigated using numerical simulations. We show that the nature of the interaction depends on whether the CME magnetic structures interact, but in all cases the result is an equilisation of the speed of the two CMEs. In the absence of magnetic interaction, the forward shock of the faster trailing CME interacts with the slow leading CME, and accelerates it. When the two CMEs have magnetic fields with the same sense of rotation, magnetic reconnection occurs between the two CMEs, leading to the formation of a single magnetic structure: in the most extreme cases, one CME "eats" the other. When the senses of rotation are opposite, reconnection does not occur, but the CMEs collide in a highly non-elastic manner, again forming a single structure. The possibility of enhanced particle acceleration in such processes is assessed. The presence of strong magnetic reconnection provides excellent opportunities for the acceleration of thermal particles, which then form a seed population for further acceleration at the CME shocks. The presence of a large population of seed particles will thus lead to an overall increase in energetic particle fluxes, as suggested by some observations.

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CMEs and Prominences and their Evolution Over the Solar Cycle

International Astronomical Union Colloquium ◽

10.1017/s0252921100048107 ◽

1998 ◽

Vol 167 ◽

pp. 463-474 ◽

Cited By ~ 4

Author(s):

David F. Webb

Keyword(s):

Solar Cycle ◽

Magnetic Flux ◽

Coronal Mass Ejections ◽

Energetic Particle ◽

Geomagnetic Storms ◽

The Sun ◽

Interplanetary Shocks ◽

X Ray ◽

Magnetic Structures ◽

Source Regions

AbstractCoronal mass ejections (CMEs) are an important aspect of coronal and interplanetary dynamics. They cause large geomagnetic storms and can drive transient interplanetary shocks, which in turn are a key source of energetic particle events. However, our knowledge of the origins and early development of CMEs at the Sun is limited. CMEs are most frequently associated with erupting prominences and long-enduring soft X-ray arcades, but sometimes with no observed surface activity. I review some of the well determined coronal properties of CMEs and what we know about their source regions, with emphasis on the characteristics of the associated prominences and helmet streamers. One of these characteristics is that many CMEs seem to arise from multipolar magnetic structures with multiple or kinked inversion lines. I also discuss the solar-cycle dependencies of these structures, including the role that erupting prominences and CMEs may play in the ejection of magnetic flux and helicity from the Sun.

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Contrast of Filament Bright Rims

International Astronomical Union Colloquium ◽

10.1017/s0252921100025628 ◽

1994 ◽

Vol 144 ◽

pp. 365-367

Author(s):

E. V. Kononovich ◽

O. B. Smirnova ◽

P. Heinzel ◽

P. Kotrč

Keyword(s):

High Altitude ◽

Line Profile ◽

Line Center ◽

Magnetic Structures ◽

The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

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Coronal Mass Ejections and Solar Filament Disappearances at Solar Maximum

International Astronomical Union Colloquium ◽

10.1017/s0252921100025161 ◽

1994 ◽

Vol 144 ◽

pp. 127-129

Author(s):

S. Dinulescu ◽

G. Maris

Keyword(s):

Coronal Mass Ejections ◽

Solar Maximum ◽

Solar Filament

AbstractOccurrence of CMEs as a result of solar filament disappearance is discussed over the cycle 22.

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