Examination of type II origin with SOHO/LASCO observations

Cho, K.-S.; Moon, Yong‐Jae; Dryer, M.; Shanmugaraju, A.; Fry, C. D.; Kim, Y.-H.; Bong, Su-Chan; Park, Y.-D.

doi:10.1029/2004ja010744

Cited by 45 publications

(35 citation statements)

References 50 publications

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“…The Type II burst speed was found to be super-Alfvénic (e.g., Vršnak & Cliver 2008;Cho et al 2005;Klein et al 1999). Furthermore, the decelerating phase of the Type II shock can be related with the fading of the Type II burst in the dynamic spectrum as the shock approaches the local Alfvén speed.…”

Section: Resultsmentioning

confidence: 99%

The formation heights of coronal shocks from 2D density and Alfvén speed maps

Zucca

Carley

Bloomfield

et al. 2014

A&A

101

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Context. Super-Alfvénic shocks associated with coronal mass ejections (CMEs) can produce radio emission known as Type II bursts. In the absence of direct imaging, accurate estimates of coronal electron densities, magnetic field strengths, and Alfvén speeds are required to calculate the kinematics of shocks. To date, 1D radial models have been used, but these are not appropriate for shocks propagating in non-radial directions. Aims. Here, we study a coronal shock wave associated with a CME and Type II radio burst using 2D electron density and Alfvén speed maps to determine the locations that shocks are excited as the CME expands through the corona. Methods. Coronal density maps were obtained from emission measures derived from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) and polarized brightness measurements from the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO). Alfvén speed maps were calculated using these density maps and magnetic field extrapolations from the Helioseismic and Magnetic Imager (SDO/HMI). The computed density and Alfvén speed maps were then used to calculate the shock kinematics in non-radial directions. Results. Using the kinematics of the Type II burst and associated shock, we find our observations to be consistent with the formation of a shock located at the CME flanks where the Alfvén speed has a local minimum. Conclusions. The 1D density models are not appropriate for shocks that propagate non-radially along the flanks of a CME. Rather, the 2D density, magnetic field and Alfvén speed maps described here give a more accurate method for determining the fundamental properties of shocks and their relation to CMEs.

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Section: Resultsmentioning

confidence: 99%

The formation heights of coronal shocks from 2D density and Alfvén speed maps

Zucca

Carley

Bloomfield

et al. 2014

A&A

101

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“…ICME transit times shown as a function of a) CME expansion speed (S-sample), b) CME plane-of-sky speed (H-sample), c) solar wind velocity (S-sample -black, H-sample -gray). The power-law least-square fit parameters are given in the insets, together with the correlation coefficient c. Cane & Richardson 2003a;Cho et al 2003;Manoharan et al 2004;Michałek et al 2004;Srivastava & Venkatakrishnan 2004;Schwenn et al 2005;Xie et al 2006). Transit times of slow CMEs range around 100 h, whereas they are grouped around 40 h in the case of the fastest CMEs.…”

Section: Resultsmentioning

confidence: 99%

“…However, the T T (v CME ) correlation is burdened by large scatter of T T values at a given v CME . The overall scatter of data points at a given v CME usually ranges around ± 1 day (see the distribution of data points in T T (v CME ) graphs in, e.g., Gopalswamy et al 2000;Gopalswamy et al 2003;Cane & Richardson 2003a;Cho et al 2003;Manoharan et al 2004;Michałek et al 2004;Srivastava & Venkatakrishnan 2004;Xie et al 2006). As emphasized by, e.g., Michałek et al (2003), Xie et al (2004), and Schwenn et al (2005), the prime reason for such a large scatter might be the difference between the measured plane-of-sky speed and the true space velocity.…”

Section: Introductionmentioning

confidence: 99%

Transit times of interplanetary coronal mass ejections and the solar wind speed

Vršnak

Žic

2007

A&A

118

107

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Aims. The Sun-Earth transit time of interplanetary coronal mass ejections (ICMEs) is one of central issues of space weather forecasting. Our aim is to find out to what degree the ICME transit time depends on the solar wind speed. Methods. Two samples of coronal mass ejections (CMEs) and the associated ICMEs are used to analyze the relationship between transit times, T T , and the solar wind speed, w, measured at 1 AU ahead and behind the ICME. Results. We found a distinct correlation T T (w), clearly showing that the transit time is dependent not only on the ICME take-off speed v CME , but also on the solar wind speed. After dividing the samples into the solar wind speed bins w ≤ 400, 400 < w ≤ 500, and w > 500 km s −1 , we compared the corresponding T T (v CME ) correlations to find that the transit times in the case of w ≤ 400 km ssubset are longer, on average, for about 20-30 h than in the case of the w > 500 km s −1 subset. Conclusions. Since the ICME transit time is significantly influenced by the solar wind speed, this effect should be included in statistical and kinematical methods of the space weather forecast.

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“…There have been many studies of the possible association of SRBT II with either flares or CMEs [153][154][155][156][157][158][159][160][161][162]. SRBT II has extensively studied to understand their sources and in connection with CMEs and Solar Energetic Particles (SEP) events [50,163] based on signatures of the shock-associated plasma oscillate signatures of type II bursts occurred near off after the maximum of chromosphere flare.…”

Section: Volume 35mentioning

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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Examination of type II origin with SOHO/LASCO observations

Cited by 45 publications

References 50 publications

The formation heights of coronal shocks from 2D density and Alfvén speed maps

The formation heights of coronal shocks from 2D density and Alfvén speed maps

Transit times of interplanetary coronal mass ejections and the solar wind speed

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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