Coronal mass ejections: 1979–1981

Howard, R. A.; Sheeley, N. R.; Koomen, M. J.; Michels, D. J.

doi:10.1029/ja090ia09p08173

Cited by 453 publications

(333 citation statements)

References 37 publications

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“…As seen from coronagraph images, streamers are the most prominent quasi-steady structures in the corona and CMEs often closely interact with streamers as they propagate outward or expand laterally (e.g., Chen et al 2010;Feng et al 2011). Statistical analyses have indicated that many CMEs originate from the streamer belt (e.g., Howard et al 1985;Hundhausen 1993;Eselevich & Tong 1997;Zhao & Webb 2003). Furthermore, recent works have shown that type II radio bursts, which are good observational manifestations of energetic electrons accelerated at shocks, reflect the interaction between shocks and streamers (e.g., Reiner et al 2003;Mancuso & Raymond 2004;Cho et al 2008;Feng et al 2012Feng et al , 2013Kong et al 2012Kong et al , 2015Chen et al 2014) or the shock passing through high-density coronal loops (e.g., Pohjolainen et al 2008;Cho et al 2013).…”

Section: Introductionmentioning

confidence: 99%

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Kong

Guo

Giacalone

et al. 2017

ApJ

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Recent observations have shown that coronal shocks driven by coronal mass ejections can develop and accelerate particles within several solar radii in large solar energetic particle (SEP) events. Motivated by this, we present an SEP acceleration study that including the process in which a fast shock propagates through a streamer-like magnetic field with both closed and open field lines in the low corona region. The acceleration of protons is modeled by numerically solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that particles can be sufficiently accelerated to up to several hundred MeV within 2-3 solar radii. When the shock propagates through a streamer-like magnetic field, particles are more efficiently accelerated compared to the case with a simple radial magnetic field, mainly due to perpendicular shock geometry and the natural trapping effect of closed magnetic fields. Our results suggest that the coronal magnetic field configuration is an important factor for producing large SEP events. We further show that the coronal magnetic field configuration strongly influences the distribution of energetic particles, leading to different locations of source regions along the shock front where most high-energy particles are concentrated. This work may have strong implications for SEP observations. The upcoming Parker Solar Probe will provide in situ observations for the distribution of energetic particles in the coronal shock region, and test the results of the study.

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Section: Introductionmentioning

confidence: 99%

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Kong

Guo

Giacalone

et al. 2017

ApJ

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“…This led to a dominant paradigm of the "loop transient". It is interesting to note that the analogous results for the first 3 years of the Solwind instrument (Howard et al, 1985) found that 2% of CMEs qualified as loops. However, the vast majority of their major events were categorised as "curved fronts" (40%), which are effectively loops without a trailing edge, so the pictures were perhaps not too inconsistent.…”

Section: Morphologymentioning

confidence: 69%

Space Storms and Space Weather Hazards

Daglis¹

2001

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Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UU Number of Pages 486REPORT DOCUMENTATION PAGE Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, -to review recent spacecraft measurements that have provided new insight into the dynamics and effects of space storms; -to review space weather hazards associated with space storms and pertinent to the operation of technological systems in space and on ground;-to discuss and assess methods of space weather forecasting, as well as national and international initiatives towards an efficient development of space climatology.Space weather, the invisible but nevertheless effective result of solar activity and solar-terrestrial coupling, has affected the operations of communication systems since the appearance of telegraph in the 19th century, though as an unknown trouble factor. Nowadays, the effects of space weather affect in various ways all communication modes, from cable to wireless to space-based systems. Moreover, space weather hazards include malfunction or even permanent damage of power distribution grids and of telecommunication, navigation and surveillance satellites, disturbances of over-the-horizon (OTH) radar, HF, VHF and UHF communications, surveying and navigation systems that use Global Positioning System (GPS) satellites, surveillance (optical and radar), and satellite tracking. Space weather influences on the Earth's weather and climate is still a developing topic. Little is known concerning the biological effects of space weather, especially regarding astronauts.This Institute could not be timelier. Space Weather, which has been defined as "conditions on the sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-and ground-based technological systems and can endanger human life", encompasses a broad range of phenomena impacting both space science and technology. The effects of Space Weather, while present throughout the solar cycle, gain particular prominence around the peak of the 11-year sunspot activity; the maximum of cycle 23 occurred in summer 2000.The fact that this ASI on Space Weather was held in Europe is particularly appropriate. European countries host a considerable repository of knowledge and world-class facilities in this field. Nevertheless, while Space Weather activities in c...

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“…It expands and is expelled by magnetic forces in CMEs. The front speeds could exceed up to 3000 kms -1 [61][62][63]. This phenomenon can exhibit a variety of forms, some having the classical "three-part" structure [64].…”

Section: Coronal Mass Ejections (Cmes)mentioning

confidence: 99%

“…Previous study also focused on the properties of CMEs such as occurrence rates, kinetic energy, the locations relative to the solar disk, angular widths, speeds and accelerations, masses, and energies [32,50,[72][73][74][75][76][77][78]. There have been many studies on the statistical properties of CMEs by [63,71,73,77,[79][80][81][82] which based on the SOHO / LASCO observations. The probable conservation of the magnetic support of the former prominence is the physical key factor for the later identification of in-situ observed magnetic clouds in the solar wind with the preexisting CMEs and before existing prominences on the disc.…”

Section: Coronal Mass Ejections (Cmes)mentioning

confidence: 99%

Probability of Solar Flares Turn out to Form a Coronal Mass Ejections Events due to the Characterization of Solar Radio Burst Type II and III

Hamidi

2014

ILCPA

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The solar flare and Coronal Mass Ejections (CMEs) are well known as one of the most massive eruptions which potentially create major disturbances in the interplanetary medium and initiate severe magnetic storms when they collide with the Earth's magnetosphere. However, how far the solar flare can contribute to the formation of the CMEs is still not easy to be understood. These phenomena are associated with II and III burst it also divided by sub-type of burst depending on the physical characteristics and different mechanisms. In this work, we used a Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy in Transportable Observatories (CALLISTO) system. The aim of the present study is to reveal dynamical properties of solar burst type II and III due to several mechanisms. Most of the cases of both solar radio bursts can be found in the range less that 400 MHz. Based on solar flare monitoring within 24 hours, the CMEs that has the potential to explode will dominantly be a class of M1 solar flare. Overall, the tendencies of SRBT III burst form the solar radio burst type III at 187 MHz to 449 MHz. Based on solar observations, it is evident that the explosive, short time-scale energy release during flares and the long term, gradual energy release expressed by CMEs can be reasonably understood only if both processes are taken as common and probably not independent signatures of a destabilization of pre-existing coronal magnetic field structures. The configurations of several active regions can be sourced regions of CMEs formation. The study of the formation, acceleration and propagation of CMEs requires advanced and powerful observational tools in different spectral ranges as many 'stages' as possible between the photosphere of the Sun and magnetosphere of the Sun and magnetosphere of the Earth. In conclusion, this range is a current regime of solar radio bursts during CMEs events.

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Coronal mass ejections: 1979–1981

Cited by 453 publications

References 37 publications

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Space Storms and Space Weather Hazards

Probability of Solar Flares Turn out to Form a Coronal Mass Ejections Events due to the Characterization of Solar Radio Burst Type II and III

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