Study of Multiple Coronal Mass Ejections at Solar Minimum Conditions

Solar Physics ◽  
2012 ◽  
Author(s):  
A. Bemporad ◽  
F. P. Zuccarello ◽  
C. Jacobs ◽  
M. Mierla ◽  
S. Poedts
Keyword(s):  
Coronal Mass Ejections ◽  
Solar Minimum

Rotation-Averaged Rates of Coronal Mass Ejections and Dynamics of Polar Crown Filaments

1994 ◽  
Vol 144 ◽  
pp. 83-89 ◽  
Author(s):  
E. W. Cliver ◽  
O. C. St. Cyr ◽  
R. A. Howard ◽  
P. S. McIntosh
Keyword(s):  
Solar Cycle ◽  
Current Sheet ◽  
Sunspot Number ◽  
Tilt Angle ◽  
Duty Cycle ◽  
Coronal Mass Ejections ◽  
Solar Minimum ◽  
Heliospheric Current Sheet ◽  
North And South ◽  
Rise Phase

AbstractWe obtained Carrington-rotation-averaged daily rates of coronal mass ejections (CMEs), corrected for duty cycle, for the period 1979-1989. The 27-day averages of CME rate and sunspot number are correlated over this 11-yr period, although significant discrepancies can occur for any given rotation. The baseline CME rate exhibited quasi-discontinuities in 1982 (decrease) and 1988 (increase) when the “tilt angle” of the heliospheric current sheet passed through values of ∼ 50°. We suggest that these quasi-discontinuities are related to the dynamics of the belts of polar crown filaments that reside at ∼ 50° north and south of the equator during solar minimum and move poleward during the rise phase of the solar cycle.

scholarly journals The Association of Solar Flares with Coronal Mass Ejections During the Extended Solar Minimum

Solar Physics ◽  
2013 ◽  
Vol 289 (4) ◽  
pp. 1257-1277 ◽  
Author(s):  
N. V. Nitta ◽  
M. J. Aschwanden ◽  
S. L. Freeland ◽  
J. R. Lemen ◽  
J.-P. Wülser ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Solar Minimum

scholarly journals Clustering of Fast Coronal Mass Ejections during Solar Cycles 23 and 24 and Implications for CME–CME Interactions

2021 ◽  
Author(s):  
Jenny Marcela Rodriguez Gomez ◽  
Tatiana Podlachikova ◽  
Astrid Veronig ◽  
Alexander Ruzmaikin ◽  
Joan Feynman ◽  
...  
Keyword(s):  
Space Weather ◽  
Coronal Mass Ejections ◽  
Solar Minimum ◽  
Geomagnetic Storms ◽  
Active Regions ◽  
Solar Cycles ◽  
Characteristic Energy ◽  
Time Index ◽  
Threshold Time ◽  
Large Flare

<p>Coronal Mass Ejections (CMEs) and their interplanetary counterparts (ICMEs) are the major sources for strong space weather disturbances. We present a study of statistical properties of fast CMEs (v≥1000 km/s) that occurred during solar cycles 23 and 24. We apply the Max Spectrum and the declustering threshold time methods. The Max Spectrum can detect the predominant clusters, and the declustering threshold time method provides details on the typical clustering properties and timescales. Our analysis shows that during the different phases of solar cycles 23 and 24, fast CMEs preferentially occur as isolated events and in clusters with, on average, two members. However, clusters with more members appear, particularly during the maximum phases of the solar cycles. During different solar cycle phases, the typical declustering timescales of fast CMEs are τ<sub>c</sub> =28-32 hrs, irrespective of the very different occurrence frequencies of CMEs during a solar minimum and maximum. These findings suggest that  τ<sub>c</sub>   for extreme events may reflect the characteristic energy build-up time for large flare and CME-prolific active regions. Statistically associating the clustering properties of fast CMEs with the disturbance storm time index at Earth suggests that fast CMEs occurring in clusters tend to produce larger geomagnetic storms than isolated fast CMEs. Our results highlight the importance of CME-CME interaction and their impact on Space Weather.</p>

scholarly journals Source Regions of Coronal Mass Ejections

2001 ◽  
Vol 203 ◽  
pp. 362-373
Author(s):  
K. P. Dere ◽  
P. Subramanian
Keyword(s):  
Active Region ◽  
Coronal Mass Ejections ◽  
Solar Minimum ◽  
Active Regions ◽  
The Other ◽  
Small Scale ◽  
Minimum Phase ◽  
Michelson Doppler Imager ◽  
Doppler Imager ◽  
Source Regions

Observations of the solar corona with the LASCO and EIT instruments on SOHO provide an unprecedented opportunity to study coronal mass ejections (CMEs) from their initiation through their evolution out to 30 R⊙. The objective of this study is to gain an understanding of the source regions from which the CMEs emanate. To this end, we have developed a list of 32 CMEs whose source regions are located on the solar disk and are well observed in EIT 195 Å data during the solar minimum phase of January 1996-May 1998. We compare the EIT source regions with photospheric magnetograms from the Michelson Doppler Imager (MDI) instrument on SOHO and the NSO/Kitt Peak Observatory and also with Hα data from various sources. The overall results of our study show that 59% of the CME related transients observed in EIT 195 Å images are associated with active regions without prominences, 22% are associated with eruptions of prominences embedded in active regions and 19% are associated with eruptions of quiescent prominences. We describe 3 especially well observed events, one from each of these 3 categories. These case studies suggest that active region CMEs are associated with active regions with lifetimes between 11-80 days. They are also often associated with small scale emerging or cancelling flux over timescales of 6-7 hours. CMEs associated with active region prominence eruptions, on the other hand, are typically associated with old active regions with lifetimes ~ 6-7 months.

scholarly journals Earth–directed coronal mass ejections and their geoeffectiveness during the 2007–2010 interval

2011 ◽  
Vol 7 (S286) ◽  
pp. 242-245
Author(s):  
Constantin Oprea ◽  
Marilena Mierla ◽  
Georgeta Maris
Keyword(s):  
Energy Transfer ◽  
Coronal Mass Ejections ◽  
Solar Minimum ◽  
Geomagnetic Storms ◽  
Coupling Function ◽  
The Sun ◽  
Good Opportunity ◽  
Stereo Mission ◽  
The Earth ◽  
Terrestrial Magnetosphere

AbstractIn this study we analyse the coronal mass ejections (CMEs) directed towards the Earth during the interval 2007–2010, using the data acquired by STEREO mission and those provided by SOHO, ACE and geomagnetic stations. A study of CMEs kinematics is performed. This is correlated with CMEs interplanetary manifestations and their geomagnetic effects, along with the energy transfer flux into magnetosphere (the Akasofu coupling function). The chosen interval that is practically coincident with the last solar minimum, offered us a good opportunity to link and analyse the chain of phenomena from the Sun to the terrestrial magnetosphere in an attempt to better understand the solar and heliospheric processes that can cause major geomagnetic storms.

Coronal Mass Ejections and Solar Filament Disappearances at Solar Maximum

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.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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