The disappearing solar filament of 2003 june 11: a three-body problem
TL;DR: In this paper, the authors show that the magnetic disturbance propagates from a mature active region to a quiescent filament by direct magnetic connection, but does so indirectly via magnetic coupling with the established region.
Abstract: The eruption of a large quiescent filament on 2003 June 11 was preceded by the birth of a nearby active region?a common scenario. In this case, however, the filament lay near a pre-existing active region and the new active region did not destabilize the filament by direct magnetic connection. Instead it appears to have done so indirectly via magnetic coupling with the established region. Restructuring between the perturbed fields of the old region and the filament then weakened the arcade overlying the midpoint of filament, where the eruption originated. The inferred rate (~11??day?1) at which the magnetic disturbance propagates from the mature region to destabilize the filament is larger than the mean speed (~5?-6??day?1) but still within the scatter obtained for Bruzek's empirical relationship between the distance from a newly formed active region to a quiescent filament and the time from active region appearance to filament disappearance. The higher propagation speed in the 2003 June 11 case may be due to the broadside (versus ''end-on) angle of attack of the (effective) new flux to the coronal magnetic fields overlying a central section of the axis of the filament.
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TL;DR: In this paper, high-resolution 2.5D MHD simulation results of magnetic breakout-initiated coronal mass ejections (CMEs) originating from a coronal pseudostreamer configuration are presented.
Abstract: We present high-resolution 2.5D MHD simulation results of magnetic breakout-initiated coronal mass ejections (CMEs) originating from a coronal pseudostreamer configuration. The coronal null point in the magnetic topology of pseudostreamers means that the initiation of consecutive sympathetic eruptions is a natural consequence of the system's evolution. A generic source region energization process—ideal footpoint shearing parallel to the pseudostreamer arcade polarity inversion lines—is all that is necessary to store sufficient magnetic energy to power consecutive CME eruptions given that the pseudostreamer topology enables the breakout initiation mechanism. The second CME occurs because the eruptive flare reconnection of the first CME simultaneously acts as the overlying pre-eruption breakout reconnection for the sympathetic eruption. We examine the details of the magnetic and kinetic energy evolution and the signatures of the overlying null point distortion, current sheet formation, and magnetic breakout reconnection giving rise to the runaway expansion that drives the flare reconnection below the erupting sheared field core. The numerical simulation's spatial resolution and output cadence are sufficient to resolve the formation of magnetic islands during the reconnection process in both the breakout and eruptive flare current sheets. We quantify the flux transfer between the pseudostreamer arcades and show that the eruptive flare reconnection processes flux ~10 times faster than the pre-eruption breakout reconnection. We show that the breakout reconnection jets cause bursty, intermittent upflows along the pseudostreamer stalk, as well as downflows in the adjacent pseudostreamer arcade, both of which may be observable as pre-eruption signatures. Finally, we examine the flux rope CME trajectories and show that the breakout current sheet provides a path of least resistance as an imbalance in the surrounding magnetic energy density and results in a non-radial CME deflection early in the eruption.
102 citations
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TL;DR: In this paper, high-resolution 2.5-dimensional MHD simulation results of magnetic breakout-initiated coronal mass ejections (CMEs) originating from a coronal pseudostreamer configuration are presented.
Abstract: We present high resolution 2.5-dimensional MHD simulation results of magnetic breakout-initiated coronal mass ejections (CMEs) originating from a coronal pseudostreamer configuration. The coronal null point in the magnetic topology of pseudostreamers means the initiation of consecutive sympathetic eruptions is a natural consequence of the system's evolution. A generic source region energization process -- ideal footpoint shearing parallel to the pseudostreamer arcade polarity inversion lines -- is all that is necessary to store sufficient magnetic energy to power consecutive CME eruptions given that the pseudostreamer topology enables the breakout initiation mechanism. The second CME occurs because the eruptive flare reconnection of the first CME simultaneously acts as the overlying pre-eruption breakout reconnection for the sympathetic eruption. We examine the details of the magnetic and kinetic energy evolution and the signatures of the overlying null point distortion, current sheet formation, and magnetic breakout reconnection giving rise to the runaway expansion that drives the flare reconnection below the erupting sheared field core. The numerical simulation's spatial resolution and output cadence are sufficient to resolve the formation of magnetic islands during the reconnection process in both the breakout and eruptive flare current sheets. We quantify the flux transfer between the pseudostreamer arcades and show the eruptive flare reconnection processes flux ~10 times faster than the pre-eruption breakout reconnection. We show that the breakout reconnection jets cause bursty, intermittent upflows along the pseudostreamer stalk as well as downflows in the adjacent pseudostreamer arcade, both of which may be observable as pre-eruption signatures. Finally, we examine the flux rope CME trajectories and show that the breakout current sheet provides a path of least resistance as an...
58 citations
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TL;DR: In this article, Tripathi et al. studied the origin and characteristics of a bright coronal downflow seen after a coronal mass ejection associated with erupting prominences on 5 March 2000 and concluded that the origin of the downflow was likely to have been magnetic reconnection taking place inside the erupting flux rope that led to its bifurcation.
Abstract: Aims: To study the origin and characteristics of a bright coronal downflow seen after a coronal mass ejection associated with erupting prominences on 5 March 2000.
Methods: This study extends that of Tripathi et al. (A&A, v. 449, pp. 369) based on the Extreme-ultraviolet Imaging Telescope (EIT), the Soft X-ray Telescope (SXT) and the Large Angle Spectrometric Coronagraph (LASCO) observations. We combined those results with an analysis of the observations taken by the H${\alpha}$ and the Mk4 coronagraphs at the Mauna Loa Solar Observatory (MLSO). The combined data-set spans a broad range of temperature as well as continuous observations from the solar surface out to 30 R$_{\sun}$.
Results: The downflow started at around 1.6R$_{\sun}$ and contained both hot and cold gas. The downflow was observed in the H${\alpha}$ and the Mk4 coronagraphs as well as the EIT and the SXT and was approximately co-spatial and co-temporal providing evidence of multi-thermal plasma. The H${\alpha}$ and Mk4 images show cusp-shaped structures close to the location where the downflow started. Mk4 observations reveal that the speed of the downflow in the early phase was substantially higher than the free-fall speed, implying a strong downward acceleration near the height at which the downflow started.
Conclusions: The origin of the downflow was likely to have been magnetic reconnection taking place inside the erupting flux rope that led to its bifurcation.
29 citations
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TL;DR: In this paper, the magnetic source locations of 142 quasi-homologous (QH) coronal mass ejections (CMEs) were identified, of which 121 are from solar cycle (SC) 23 and 21 from SC 24.
Abstract: In this paper, we identified the magnetic source locations of 142 quasi-homologous (QH) coronal mass ejections (CMEs), of which 121 are from solar cycle (SC) 23 and 21 from SC 24. Among those CMEs, 63% originated from the same source location as their predecessor (defined as S-type), while 37% originated from a different location within the same active region as their predecessor (defined as D-type). Their distinctly different waiting time distributions, peaking around 7.5 and 1.5 hr for S- and D-type CMEs, suggest that they might involve different physical mechanisms with different characteristic timescales. Through detailed analysis based on nonlinear force-free coronal magnetic field modeling of two exemplary cases, we propose that the S-type QH CMES might involve a recurring energy release process from the same source location (by magnetic free energy replenishment), whereas the D-type QH CMEs can happen when a flux tube system is disturbed by a nearby CME.
26 citations
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References
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TL;DR: The Large Angle Spectroscopic Coronagraph (LASCO) is a triple coronagraph being jointly developed for the Solar and Heliospheric Observatory (SOHO) mission as discussed by the authors.
Abstract: The Large Angle Spectroscopic Coronagraph (LASCO) is a triple coronagraph being jointly developed for the Solar and Heliospheric Observatory (SOHO) mission LASCO comprises three nested coronagraphs (C1, C2, and C3) that image the solar corona for 11 to 30 solar radii (C1: 11 to 3 solar radii, C2: 15 to 6 solar radii, and C3: 3 to 300 solar radii) The inner coronagraph (C1) is a newly developed mirror version of the classic Lyot coronagraph without an external occultor, while the middle coronagraph (C2) and the outer coronagraph (C3) are externally occulted instruments High resolution coronal spectroscopy from 11 to 3 R solar radii can be performed by using a Fabry-Perot interferometer, which is part of C1 High volume memories and a high speed microprocessor enable extensive onboard image processing Image compression by factors of 10 to 20 will result in the transmission of 10 to 20 full images per hour
2,273 citations
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TL;DR: The Michelson Doppler Imager (MDI) as mentioned in this paper was used to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations, revealing the static and dynamic properties of the convection zone and core.
Abstract: The Solar Oscillations Investigation (SOI) uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations. Characteristics of the modes reveal the static and dynamic properties of the convection zone and core. Knowledge of these properties will improve our understanding of the solar cycle and of stellar evolution. Other photospheric observations will contribute to our knowledge of the solar magnetic field and surface motions. The investigation consists of coordinated efforts by several teams pursuing specific scientific objectives. The instrument images the Sun on a 10242 CCD camera through a series of increasingly narrow spectral filters. The final elements, a pair of tunable Michelson interferometers, enable MDI to record filtergrams with a FWHM bandwidth of 94 mA. Normally 20 images centered at 5 wavelengths near the Ni I 6768 spectral line are recorded each minute. MDI calculates velocity and continuum intensity from the filtergrams with a resolution of 4″ over the whole disk. An extensive calibration program has verified the end-to-end performance of the instrument. To provide continuous observations of the longest-lived modes that reveal the internal structure of the Sun, a carefully-selected set of spatial averages are computed and downlinked at all times. About half the time MDI will also be able to downlink complete velocity and intensity images each minute. This high rate telemetry (HRT) coverage is available for at least a continuous 60-day interval each year and for 8 hours each day during the rest of the year. During the 8-hour HRT intervals, 10 of the exposures each minute can be programmed for other observations, such as measurements in MDI's higher resolution (1.25″) field centered about 160″ north of the equator; meanwhile, the continuous structure program proceeds during the other half minute. Several times each day, polarizers will be inserted to measure the line-of-sight magnetic field. MDI operations will be scheduled well in advance and will vary only during the daily 8-hour campaigns. Quick-look and summary data, including magnetograms, will be processed immediately. Most high-rate data will be delivered only by mail to the SOI Science Support Center (SSSC) at Stanford, where a processing pipeline will produce 3 Terabytes of calibrated data products each year. These data products will be analyzed using the SSSC and the distributed resources of the co-investigators. The data will be available for collaborative investigations.
2,075 citations
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TL;DR: The Solar Oscillations Investigation (SOI) as mentioned in this paper uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations.
Abstract: The Solar Oscillations Investigation (SOI) uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations. Characteristics of the modes reveal the static and dynamic properties of the convection zone and core. Knowledge of these properties will improve our understanding of the solar cycle and of stellar evolution. Other photospheric observations will contribute to our knowledge of the solar magnetic field and surface motions. The investigation consists of coordinated efforts by several teams pursuing specific scientific objectives.
1,868 citations
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TL;DR: The Extreme-ultraviolet Imaging Telescope (EIT) as discussed by the authors provides wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb.
Abstract: The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated optics will select spectral emission lines from Fe IX (171 A), Fe XII (195 A), Fe XV (284 A), and He II (304 A) to provide sensitive temperature diagnostics in the range from 6 × 104 K to 3 × 10 6 K. The telescope has a 45×45 arcmin field of view and 2.6 arcsec pixels which will provide approximately 5-arcsec spatial resolution. The EIT will probe the coronal plasma on a global scale, as well as the underlying cooler and turbulent atmosphere, providing the basis for comparative analyses with observations from both the ground and other SOHO instruments. This paper presents details of the EIT instrumentation, its performance and operating modes.
1,797 citations
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TL;DR: The Large Angle Spectroscopic Coronagraph (LASCO) is a three coronagraph package which has been jointly developed for the Solar and Heliospheric Observatory (SOHO) mission by the Naval Research Laboratory (USA), the Laboratoire d'Astronomie Spatiale (France), the Max-Planck-Institut fur Aeronomie (Germany), and the University of Birmingham (UK) as discussed by the authors.
Abstract: The Large Angle Spectroscopic Coronagraph (LASCO) is a three coronagraph package which has been jointly developed for the Solar and Heliospheric Observatory (SOHO) mission by the Naval Research Laboratory (USA), the Laboratoire d’Astronomie Spatiale (France), the Max-Planck-Institut fur Aeronomie (Germany), and the University of Birmingham (UK) LASCO comprises three coronagraphs, C1, C2, and C3, that together image the solar corona from 11 to 30 R⊙ (C1: 11–3 R⊙, C2: 15–6 R⊙, and C3: 37 – 30 R⊙) The C1 coronagraph is a newly developed mirror version of the classic internally-occulted Lyot coronagraph, while the C2 and C3 coronagraphs are externally occulted instruments High-resolution imaging spectroscopy of the corona from 11 to 3 R⊙ can be performed with the Fabry-Perot interferometer in C1 High-volume memories and a high-speed microprocessor enable extensive on-board image processing Image compression by a factor of about 10 will result in the transmission of 10 full images per hour
1,688 citations