scholarly journals Statistical relationship between solar flares and coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 233-243 ◽  
Author(s):  
Seiji Yashiro ◽  
Nat Gopalswamy
Keyword(s):  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Large Angle ◽  
Outer Edge ◽  
Heliospheric Observatory ◽  
X Ray ◽  
The Difference ◽  
Statistical Relationships ◽  
Flare Site ◽  
Spectrometric Coronagraph

AbstractWe report on the statistical relationships between solar flares and coronal mass ejections (CMEs) observed during 1996-2007 inclusively. We used soft X-ray flares observed by the Geostationary Operational Environmental Satellite (GOES) and CMEs observed by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) mission. Main results are (1) the CME association rate increases with flare's peak flux, fluence, and duration, (2) the difference between flare and CME onsets shows a Gaussian distribution with the standard deviation σ = 17 min (σ = 15 min) for the first (second) order extrapolated CME onset, (3) the most frequent flare site is under the center of the CME span, not near one leg (outer edge) of the CMEs, (4) a good correlation was found between the flare fluence versus the CME kinetic energy. Implications for flare-CME models are discussed.

scholarly journals The Propagation of an Impulsive Coronal Mass Ejections (CMEs) due to the High Solar Flares and Moreton Waves

2014 ◽  
Vol 33 ◽  
pp. 118-126 ◽  
Author(s):  
Zety Sharizat Hamidi ◽  
N.N.M. Shariff
Keyword(s):  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Large Angle ◽  
Short Review ◽  
North West ◽  
The North ◽  
West Region ◽  
Basic Concepts ◽  
Mass Ejection ◽  
Spectrometric Coronagraph

This paper provides a short review of some of the basic concepts related to the origin of Coronal Mass Ejections (CMEs). The numerous ideas which have been put forward to elucidate the initiation of CMEs are categorized in terms of whether this event is a gradual CME or impulsive CME. In this case, an earth-directed Coronal Mass Ejection (CME) was observed on April 2, 2014 by the Large Angle Spectrometric Coronagraph (LASCO) C2. This recent observations obtained a large impulsive CMEs. The CME, originating from the active region AR2027. The speed of CMEs is 1600 kms-1. A halo CME, a bright expanding ring at the North- West region is exploded beginning at about 14:36 UT, and the process of departing, expansion and propagation are highlighted. We discuss the correspondence of this event with the structure of the CME in the LASCO data. It is believed that the high solar flare and a Moreton waves initiate this kind of CMEs

Collaborative VLA and LASCO Observations of Nonthermal Energy Release in the Corona

2001 ◽  
Vol 203 ◽  
pp. 520-522
Author(s):  
R. F. Willson
Keyword(s):  
Coronal Mass Ejections ◽  
Large Angle ◽  
Large Array ◽  
Related Activity ◽  
Heliospheric Observatory ◽  
Very Large Array ◽  
X Ray ◽  
Abrupt Changes ◽  
Coronal Magnetic Fields ◽  
Burst Emission

We discuss recent collaborative observations of coronal mass ejections and related activity using the Very Large Array (VLA) and the Solar and Heliospheric Observatory (SOHO). VLA observations show the onset of intense 400 cm burst emission during an X1 GOES soft X-ray burst observed by the Yohkoh spacecraft and prior to a CME observed by the Large Angle Spectroscometric C2 Coronagraph (LASCO) on board SOHO. VLA snapshot maps show that the 400 cm burst site varied discontinuously throughout the course of the flare, possibly reflecting abrupt changes in the structure of the coronal magnetic fields along which the energetic particles traveled.

scholarly journals Large‐Angle Spectrometric Coronagraph Measurements of the Energetics of Coronal Mass Ejections

2000 ◽  
Vol 534 (1) ◽  
pp. 456-467 ◽  
Author(s):  
A. Vourlidas ◽  
P. Subramanian ◽  
K. P. Dere ◽  
R. A. Howard
Keyword(s):  
Coronal Mass Ejections ◽  
Large Angle ◽  
Spectrometric Coronagraph

Solar and Heliospheric Observatory/Large Angle Spectrometric Coronagraph Polarimetric Calibration

Solar Physics ◽  
2006 ◽  
Vol 237 (1) ◽  
pp. 211-222 ◽  
Author(s):  
Thomas G. Moran ◽  
Joseph M. Davila ◽  
Jeff S. Morrill ◽  
Dennis Wang ◽  
Russel Howard
Keyword(s):  
Large Angle ◽  
Heliospheric Observatory ◽  
Spectrometric Coronagraph ◽  
Polarimetric Calibration

scholarly journals Difference of source regions between fast and slow coronal mass ejections

2019 ◽  
Vol 36 ◽  
Author(s):  
B. Filippov
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Magnetic Energy ◽  
Active Regions ◽  
Coronal Magnetic Field ◽  
Source Regions ◽  
Free Magnetic Energy ◽  
The Difference ◽  
Sunspot Groups

Abstract Coronal mass ejections (CMEs) are tightly related to filament eruptions and usually are their continuation in the upper solar corona. It is common practice to divide all observed CMEs into fast and slow ones. Fast CMEs usually follow eruptive events in active regions near big sunspot groups and associated with major solar flares. Slow CMEs are more related to eruptions of quiescent prominences located far from active regions. We analyse 10 eruptive events with particular attention to the events on 2013 September 29 and on 2016 January 26, one of which was associated with a fast CME, while another was followed by a slow CME. We estimated the initial store of free magnetic energy in the two regions and show the resemblance of pre-eruptive situations. The difference of late behaviour of the two eruptive prominences is a consequence of the different structure of magnetic field above the filaments. We estimated this structure on the basis of potential magnetic field calculations. Analysis of other eight events confirmed that all fast CMEs originate in regions with rapidly changing with height value and direction of coronal magnetic field.

scholarly journals Analysis and modeling of the dynamics of the glow of calcium and hydrogen lines in solar and stellar flares

2021 ◽  
Vol 30 (1) ◽  
pp. 91-95
Author(s):  
Yurij Alekseevich Kupryakov ◽  
Konstantin Veniaminovich Bychkov ◽  
Oksana Mikhailovna Belova ◽  
Alexey Borisovich Gorshkov ◽  
Petr Heinzel ◽  
...  
Keyword(s):  
Solar Flares ◽  
Radiation Flux ◽  
Temporal Variations ◽  
Slow Heating ◽  
X Ray ◽  
Stellar Flares ◽  
Flare Stars ◽  
The Difference ◽  
Ev Lac ◽  
Hydrogen Lines

Abstract We present intensity curves of solar flares obtained in the Hα hydrogen line and CaII H, CaIR 8542Å lines using multichannel spectrographs of Ondřejov Observatory (Czech Republic) for the period 2000–2012. The general behavior of observed intensity curves is practically the same for all flares and is consistent with temporal variations of X-ray emission. However, our results differ significantly from those obtained by other authors for selected flare stars, for example, AD Leo; EV Lac; YZ CMi. We tried to explain the difference in the behavior of Ca II and Hα radiation flux by appearance of a shock wave during a flare and slow heating of the plasma.

scholarly journals Major solar flares without coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 283-286 ◽  
Author(s):  
N. Gopalswamy ◽  
S. Akiyama ◽  
S. Yashiro
Keyword(s):  
Open Field ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Active Regions ◽  
High Energy ◽  
X Ray ◽  
Type Iii ◽  
High Energy Electrons ◽  
Field Lines ◽  
Microwave Bursts

AbstractWe examine the source properties of X-class soft X-ray flares that were not associated with coronal mass ejections (CMEs). All the flares were associated with intense microwave bursts implying the production of high energy electrons. However, most (85%) of the flares were not associated with metric type III bursts, even though open field lines existed in all but two of the active regions. The X-class flares seem to be truly confined because there was no material ejection (thermal or nonthermal) away from the flaring region into space.

scholarly journals LASCO and EIT Observations of the Dynamic Corona

1998 ◽  
Vol 11 (2) ◽  
pp. 861-864
Author(s):  
K. P. Dere ◽  
G. E. Brueckner
Keyword(s):  
High Speed ◽  
Extreme Ultraviolet ◽  
Spatial Scales ◽  
Coronal Holes ◽  
Large Angle ◽  
Solar Radius ◽  
Heliospheric Observatory ◽  
Combined Operations ◽  
Imaging Telescope ◽  
Spectrometric Coronagraph

The combined operations of the Large Angle Spectrometric Coronagraph (LASCO) and the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO), launched in December 1995, have provided an unprecedented opportunity for observing essentially all coronal phenomena that are not hidden behind the disk of the Sun. Consequently, observations with these instrument are providing information on coronal mass ejections (CMEs) from their initiation through their development over 30 ⊙. They reveal a coronal that never reaches a steady state. The corona is the site of continuous, time-dependent outflows, both within the coronal holes and the high speed streams and in the streamer belts and their mid-latitude sources. The spatial scales of these outflows range from 10s of arc-seconds through about a solar radius in large CMEs.

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