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Bojan Vršnak - One of the best experts on this subject based on the ideXlab platform.
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impulsive Acceleration of coronal mass ejections ii relation to soft x ray flares and filament eruptions
The Astrophysical Journal, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights, and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME Acceleration ends after the soft X-ray (SXR) Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than ±5 minutes, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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impulsive Acceleration of coronal mass ejections ii relation to sxr flares and filament eruptions
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1 and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 CMEs in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events which were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration, and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME accleration ends after the SXR Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than \pm5 min, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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impulsive Acceleration of coronal mass ejections i statistics and cme source region characteristics
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B. M. Bein, Nicolas Muhr, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs), from their initiation, through the impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity and Acceleration profiles and statistically analysed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration and size of the CME source region. The CME Peak Accelerations derived range from 20 to 6800 m s^2 and are inversely correlated to the Acceleration duration and to the height at Peak Acceleration. 74% of the events reach their Peak Acceleration at heights below 0.5 Rsun. CMEs which originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
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IMPULSIVE Acceleration OF CORONAL MASS EJECTIONS. I. STATISTICS AND CORONAL MASS EJECTION SOURCE REGION CHARACTERISTICS
The Astrophysical Journal, 2011Co-Authors: B. M. Bein, Nicolas Muhr, S. Berkebile-stoiser, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs) from their initiation through impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity, and Acceleration profiles and statistically analyzed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration, and size of the CME source region. The CME Peak Accelerations we derived range from 20 to 6800 m s-2 and are inversely correlated with the Acceleration duration and the height at Peak Acceleration. Seventy-four percent of the events reach their Peak Acceleration at heights below 0.5 R sun. CMEs that originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
B. M. Bein - One of the best experts on this subject based on the ideXlab platform.
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impulsive Acceleration of coronal mass ejections ii relation to soft x ray flares and filament eruptions
The Astrophysical Journal, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights, and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME Acceleration ends after the soft X-ray (SXR) Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than ±5 minutes, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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relation between the coronal mass ejection Acceleration and the non thermal flare characteristics
The Astrophysical Journal, 2012Co-Authors: S Berkebilestoiser, B. M. Bein, A. M. Veronig, Manuela TemmerAbstract:We investigate the relationship between the main Acceleration phase of coronal mass ejections (CMEs) and the particle Acceleration in the associated flares as evidenced in Reuven Ramaty High Energy Solar Spectroscopic Imager non-thermal X-rays for a set of 37 impulsive flare-CME events. Both the CME Peak velocity and Peak Acceleration yield distinct correlations with various parameters characterizing the flare-accelerated electron spectra. The highest correlation coefficient is obtained for the relation of the CME Peak velocity and the total energy in accelerated electrons (c = 0.85), supporting the idea that the Acceleration of the CME and the particle Acceleration in the associated flare draw their energy from a common source, probably magnetic reconnection in the current sheet behind the erupting structure. In general, the CME Peak velocity shows somewhat higher correlations with the non-thermal flare parameters than the CME Peak Acceleration, except for the spectral index of the accelerated electron spectrum, which yields a higher correlation with the CME Peak Acceleration (c ?0.6), indicating that the hardness of the flare-accelerated electron spectrum is tightly coupled to the impulsive Acceleration process of the rising CME structure. We also obtained high correlations between the CME initiation height h 0 and the non-thermal flare parameters, with the highest correlation of h 0 to the spectral index ? of flare-accelerated electrons (c 0.8). This means that CMEs erupting at low coronal heights, i.e., in regions of stronger magnetic fields, are accompanied by flares that are more efficient at accelerating electrons to high energies. In the majority of events (~80%), the non-thermal flare emission starts after the CME Acceleration, on average delayed by 6 minutes, in line with the standard flare model where the rising flux rope stretches the field lines underneath until magnetic reconnection sets in. We find that the current sheet length at the onset of magnetic reconnection is 21 ? 7?Mm. The flare hard X-ray Peaks are well synchronized with the Peak of the CME Acceleration profile, and in 75% of the cases they occur within ?5?minutes. Our findings provide strong evidence for the tight coupling between the CME dynamics and the particle Acceleration in the associated flare in impulsive events, with the total energy in accelerated electrons being closely correlated with the Peak velocity (and thus the kinetic energy) of the CME, whereas the number of electrons accelerated to high energies is decisively related to the CME Peak Acceleration and the height of the pre-eruptive structure.
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impulsive Acceleration of coronal mass ejections ii relation to sxr flares and filament eruptions
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1 and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 CMEs in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events which were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration, and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME accleration ends after the SXR Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than \pm5 min, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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impulsive Acceleration of coronal mass ejections i statistics and cme source region characteristics
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B. M. Bein, Nicolas Muhr, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs), from their initiation, through the impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity and Acceleration profiles and statistically analysed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration and size of the CME source region. The CME Peak Accelerations derived range from 20 to 6800 m s^2 and are inversely correlated to the Acceleration duration and to the height at Peak Acceleration. 74% of the events reach their Peak Acceleration at heights below 0.5 Rsun. CMEs which originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
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IMPULSIVE Acceleration OF CORONAL MASS EJECTIONS. I. STATISTICS AND CORONAL MASS EJECTION SOURCE REGION CHARACTERISTICS
The Astrophysical Journal, 2011Co-Authors: B. M. Bein, Nicolas Muhr, S. Berkebile-stoiser, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs) from their initiation through impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity, and Acceleration profiles and statistically analyzed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration, and size of the CME source region. The CME Peak Accelerations we derived range from 20 to 6800 m s-2 and are inversely correlated with the Acceleration duration and the height at Peak Acceleration. Seventy-four percent of the events reach their Peak Acceleration at heights below 0.5 R sun. CMEs that originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
Manuela Temmer - One of the best experts on this subject based on the ideXlab platform.
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impulsive Acceleration of coronal mass ejections ii relation to soft x ray flares and filament eruptions
The Astrophysical Journal, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights, and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME Acceleration ends after the soft X-ray (SXR) Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than ±5 minutes, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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relation between the coronal mass ejection Acceleration and the non thermal flare characteristics
The Astrophysical Journal, 2012Co-Authors: S Berkebilestoiser, B. M. Bein, A. M. Veronig, Manuela TemmerAbstract:We investigate the relationship between the main Acceleration phase of coronal mass ejections (CMEs) and the particle Acceleration in the associated flares as evidenced in Reuven Ramaty High Energy Solar Spectroscopic Imager non-thermal X-rays for a set of 37 impulsive flare-CME events. Both the CME Peak velocity and Peak Acceleration yield distinct correlations with various parameters characterizing the flare-accelerated electron spectra. The highest correlation coefficient is obtained for the relation of the CME Peak velocity and the total energy in accelerated electrons (c = 0.85), supporting the idea that the Acceleration of the CME and the particle Acceleration in the associated flare draw their energy from a common source, probably magnetic reconnection in the current sheet behind the erupting structure. In general, the CME Peak velocity shows somewhat higher correlations with the non-thermal flare parameters than the CME Peak Acceleration, except for the spectral index of the accelerated electron spectrum, which yields a higher correlation with the CME Peak Acceleration (c ?0.6), indicating that the hardness of the flare-accelerated electron spectrum is tightly coupled to the impulsive Acceleration process of the rising CME structure. We also obtained high correlations between the CME initiation height h 0 and the non-thermal flare parameters, with the highest correlation of h 0 to the spectral index ? of flare-accelerated electrons (c 0.8). This means that CMEs erupting at low coronal heights, i.e., in regions of stronger magnetic fields, are accompanied by flares that are more efficient at accelerating electrons to high energies. In the majority of events (~80%), the non-thermal flare emission starts after the CME Acceleration, on average delayed by 6 minutes, in line with the standard flare model where the rising flux rope stretches the field lines underneath until magnetic reconnection sets in. We find that the current sheet length at the onset of magnetic reconnection is 21 ? 7?Mm. The flare hard X-ray Peaks are well synchronized with the Peak of the CME Acceleration profile, and in 75% of the cases they occur within ?5?minutes. Our findings provide strong evidence for the tight coupling between the CME dynamics and the particle Acceleration in the associated flare in impulsive events, with the total energy in accelerated electrons being closely correlated with the Peak velocity (and thus the kinetic energy) of the CME, whereas the number of electrons accelerated to high energies is decisively related to the CME Peak Acceleration and the height of the pre-eruptive structure.
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impulsive Acceleration of coronal mass ejections ii relation to sxr flares and filament eruptions
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1 and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 CMEs in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events which were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration, and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME accleration ends after the SXR Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than \pm5 min, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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impulsive Acceleration of coronal mass ejections i statistics and cme source region characteristics
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B. M. Bein, Nicolas Muhr, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs), from their initiation, through the impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity and Acceleration profiles and statistically analysed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration and size of the CME source region. The CME Peak Accelerations derived range from 20 to 6800 m s^2 and are inversely correlated to the Acceleration duration and to the height at Peak Acceleration. 74% of the events reach their Peak Acceleration at heights below 0.5 Rsun. CMEs which originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
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IMPULSIVE Acceleration OF CORONAL MASS EJECTIONS. I. STATISTICS AND CORONAL MASS EJECTION SOURCE REGION CHARACTERISTICS
The Astrophysical Journal, 2011Co-Authors: B. M. Bein, Nicolas Muhr, S. Berkebile-stoiser, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs) from their initiation through impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity, and Acceleration profiles and statistically analyzed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration, and size of the CME source region. The CME Peak Accelerations we derived range from 20 to 6800 m s-2 and are inversely correlated with the Acceleration duration and the height at Peak Acceleration. Seventy-four percent of the events reach their Peak Acceleration at heights below 0.5 R sun. CMEs that originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
A. M. Veronig - One of the best experts on this subject based on the ideXlab platform.
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impulsive Acceleration of coronal mass ejections ii relation to soft x ray flares and filament eruptions
The Astrophysical Journal, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights, and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME Acceleration ends after the soft X-ray (SXR) Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than ±5 minutes, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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relation between the coronal mass ejection Acceleration and the non thermal flare characteristics
The Astrophysical Journal, 2012Co-Authors: S Berkebilestoiser, B. M. Bein, A. M. Veronig, Manuela TemmerAbstract:We investigate the relationship between the main Acceleration phase of coronal mass ejections (CMEs) and the particle Acceleration in the associated flares as evidenced in Reuven Ramaty High Energy Solar Spectroscopic Imager non-thermal X-rays for a set of 37 impulsive flare-CME events. Both the CME Peak velocity and Peak Acceleration yield distinct correlations with various parameters characterizing the flare-accelerated electron spectra. The highest correlation coefficient is obtained for the relation of the CME Peak velocity and the total energy in accelerated electrons (c = 0.85), supporting the idea that the Acceleration of the CME and the particle Acceleration in the associated flare draw their energy from a common source, probably magnetic reconnection in the current sheet behind the erupting structure. In general, the CME Peak velocity shows somewhat higher correlations with the non-thermal flare parameters than the CME Peak Acceleration, except for the spectral index of the accelerated electron spectrum, which yields a higher correlation with the CME Peak Acceleration (c ?0.6), indicating that the hardness of the flare-accelerated electron spectrum is tightly coupled to the impulsive Acceleration process of the rising CME structure. We also obtained high correlations between the CME initiation height h 0 and the non-thermal flare parameters, with the highest correlation of h 0 to the spectral index ? of flare-accelerated electrons (c 0.8). This means that CMEs erupting at low coronal heights, i.e., in regions of stronger magnetic fields, are accompanied by flares that are more efficient at accelerating electrons to high energies. In the majority of events (~80%), the non-thermal flare emission starts after the CME Acceleration, on average delayed by 6 minutes, in line with the standard flare model where the rising flux rope stretches the field lines underneath until magnetic reconnection sets in. We find that the current sheet length at the onset of magnetic reconnection is 21 ? 7?Mm. The flare hard X-ray Peaks are well synchronized with the Peak of the CME Acceleration profile, and in 75% of the cases they occur within ?5?minutes. Our findings provide strong evidence for the tight coupling between the CME dynamics and the particle Acceleration in the associated flare in impulsive events, with the total energy in accelerated electrons being closely correlated with the Peak velocity (and thus the kinetic energy) of the CME, whereas the number of electrons accelerated to high energies is decisively related to the CME Peak Acceleration and the height of the pre-eruptive structure.
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impulsive Acceleration of coronal mass ejections ii relation to sxr flares and filament eruptions
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: B. M. Bein, A. M. Veronig, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:Using high time cadence images from the STEREO EUVI, COR1 and COR2 instruments, we derived detailed kinematics of the main Acceleration stage for a sample of 95 CMEs in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher Peak Accelerations and lower Acceleration phase durations, initiation heights and heights, at which they reach their Peak velocities and Peak Accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive Accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME Peak Acceleration significantly lower values than for events which were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME Acceleration duration, and negatively correlated with the CME Peak Acceleration. For the majority of the events the CME Acceleration starts before the flare onset (for 75% of the events) and the CME accleration ends after the SXR Peak time (for 77% of the events). In ~60% of the events, the time difference between the Peak time of the flare SXR flux derivative and the Peak time of the CME Acceleration is smaller than \pm5 min, which hints at a feedback relationship between the CME Acceleration and the energy release in the associated flare due to magnetic reconnection.
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impulsive Acceleration of coronal mass ejections i statistics and cme source region characteristics
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: B. M. Bein, Nicolas Muhr, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, S Berkebilestoiser, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs), from their initiation, through the impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity and Acceleration profiles and statistically analysed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration and size of the CME source region. The CME Peak Accelerations derived range from 20 to 6800 m s^2 and are inversely correlated to the Acceleration duration and to the height at Peak Acceleration. 74% of the events reach their Peak Acceleration at heights below 0.5 Rsun. CMEs which originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
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IMPULSIVE Acceleration OF CORONAL MASS EJECTIONS. I. STATISTICS AND CORONAL MASS EJECTION SOURCE REGION CHARACTERISTICS
The Astrophysical Journal, 2011Co-Authors: B. M. Bein, Nicolas Muhr, S. Berkebile-stoiser, A. M. Veronig, I. Kienreich, D. Utz, Manuela Temmer, Bojan VršnakAbstract:We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs) from their initiation through impulsive Acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity, and Acceleration profiles and statistically analyzed characteristic CME parameters: Peak Acceleration, Peak velocity, Acceleration duration, initiation height, height at Peak velocity, height at Peak Acceleration, and size of the CME source region. The CME Peak Accelerations we derived range from 20 to 6800 m s-2 and are inversely correlated with the Acceleration duration and the height at Peak Acceleration. Seventy-four percent of the events reach their Peak Acceleration at heights below 0.5 R sun. CMEs that originate from compact sources low in the corona are more impulsive and reach higher Peak Accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME Accelerations and decreases with height and CME size.
Jeanrobert Altidor - One of the best experts on this subject based on the ideXlab platform.
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estimation of Peak ground Acceleration from horizontal rigid body displacement a case study in port au prince haiti
Bulletin of the Seismological Society of America, 2012Co-Authors: Susan E Hough, Tomoyo Taniguchi, Jeanrobert AltidorAbstract:The M 7.0 Haiti earthquake of 12 January 2010 caused catastrophic da- mage and loss of life in the capital city of Port-au-Prince. The extent of the damage was primarily due to poor construction and high population density. The earthquake was recorded by only a single seismic instrument within Haiti, an educational seis- mometer that was neither bolted to the ground nor able to record strong motion on scale. The severity of near-field mainshock ground motions, in Port-au-Prince and elsewhere, has thus remained unclear. We present a detailed, quantitative analysis of the marks left on a tile floor by an industrial battery rack that was displaced by the earthquake in the Canape Vert neighborhood in the southern Port-au-Prince metropolitan region. Results of this analysis, based on a recently developed formula- tion for predicted rigid body displacement caused by sinusoidal ground Acceleration, indicate that mainshock shaking at Canape Vert was approximately 0:5g, correspond- ing to a modified Mercalli intensity of VIII. Combining this result with the weak- motion amplification factor estimated from aftershock recordings at the site as well as a general assessment of macroseismic effects, we estimate the Peak Acceleration to be ≈0:2g for sites in central Port-au-Prince that experienced relatively moderate damage and where estimated weak-motion site amplification is lower than that at the Canape Vert site. We also analyze a second case of documented rigid body dis- placement, at a location less than 2 km from the Canape Vert site, and estimate the Peak Acceleration to be approximately 0:4g at this location. Our results illustrate how observations of rigid body horizontal displacement during earthquakes can be used to estimate Peak ground Acceleration in the absence of instrumental data.
