Possible observation of a disconnected magnetic structure in a coronal transient

Illing, R. M. E.; Hundhausen, A. J.

doi:10.1029/ja088ia12p10210

Cited by 72 publications

(40 citation statements)

References 22 publications

(10 reference statements)

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“…11 shows a classical three-part ("light-bulb") CME morphology in a coronagraph image. The low density "dark cavity" corresponds to the flux rope, while the brightest features are a dense prominence core and a frontal rim of coronal loops that pile up at the flux rope leading edge (Illing and Hundhausen 1983;Dere et al 1999;Gibson and Low 2000). The excess mass image in the right-hand panel of Fig.…”

Section: Connection Between Icmes and Cmesmentioning

confidence: 99%

Coronal mass ejections and their sheath regions in interplanetary space

Kilpua

Koskinen

Pulkkinen

2017

Living Rev Sol Phys

356

360

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Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

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Section: Connection Between Icmes and Cmesmentioning

confidence: 99%

Coronal mass ejections and their sheath regions in interplanetary space

Kilpua

Koskinen

Pulkkinen

2017

Living Rev Sol Phys

356

360

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“…T hree-Part Structure of Magnetic Field About one-third of CMEs observed in white light at the solar limb have a classical three-part structure (Illing & Hundhausen 1983) (Fig. 2a).…”

Section: Formation Of Sigmoid-arcade Conðgurations Andmentioning

confidence: 99%

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Tokman

Bellan

2002

ApJ

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We present a new three-dimensional magnetohydrodynamic (MHD) model that describes the evolution of coronal magnetic arcades in response to photospheric Ñows. The dynamics of the system is discussed, and it is shown that the model reproduces a number of features characteristic of coronal mass ejection (CME) observations. In particular, we propose explanations for the three-part structure of CMEs observed at the solar limb and the formation and evolution of sigmoids and overlaying arcades. The model includes the e †ects of Ðnite resistivity in the system and morphological changes induced by reconnection are studied. Reconnection is found to prevent the formation of highly twisted magnetic structures if the magnitude of photospheric velocity is close to the observed values. In addition, we suggest a novel explanation for the splitting of the CMEÏs core prominence material observed in some eruptions. The distinguishing features of the model are the novel numerical methods used to evolve the MHD system and the formulation of the boundary conditions. The sti †ness of the resistive MHD equations constitutes a major difficulty for numerical simulations. Calculations in our model are performed using recently introduced exponential propagation techniques that allow efficient integration of the equations with time steps far exceeding the CFL bound that constrains explicit schemes.

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“…White-light coronagraph observations in the past decades have revealed that many CMEs display a characteristic threepart structure: a bright loop-like leading front (LF), a dark cavity underneath, and an embedded bright compact core (Illing & Hundhausen 1983). When a pre-CME structure lifts off from the associated source region, it can cause the expansion and successive stretching of the overlying magnetic field lines to form a CME.…”

Section: Introductionmentioning

confidence: 99%

Differential Emission Measure Analysis of Multiple Structural Components of Coronal Mass Ejections in the Inner Corona

Cheng

Zhang

Saar

et al. 2012

ApJ

267

249

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In this paper, we study the temperature and density properties of multiple structural components of coronal mass ejections (CMEs) using differential emission measure (DEM) analysis. The DEM analysis is based on the sixpassband EUV observations of solar corona from the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory. The structural components studied include the hot channel in the core region (presumably the magnetic flux rope of the CME), the bright loop-like leading front (LF), and coronal dimming in the wake of the CME. We find that the presumed flux rope has the highest average temperature (>8 MK) and density (∼1.0 × 10 9 cm −3 ), resulting in an enhanced emission measure over a broad temperature range (3 T(MK) 20). On the other hand, the CME LF has a relatively cool temperature (∼2 MK) and a narrow temperature distribution similar to the pre-eruption coronal temperature (1 T(MK) 3). The density in the LF, however, is increased by 2%-32% compared with that of the pre-eruption corona, depending on the event and location. In coronal dimmings, the temperature is more broadly distributed (1 T(MK) 4), but the density decreases by ∼35%-∼40%. These observational results show that: (1) CME core regions are significantly heated, presumably through magnetic reconnection; (2) CME LFs are a consequence of compression of ambient plasma caused by the expansion of the CME core region; and (3) the dimmings are largely caused by the plasma rarefaction associated with the eruption.

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Possible observation of a disconnected magnetic structure in a coronal transient

Cited by 72 publications

References 22 publications

Coronal mass ejections and their sheath regions in interplanetary space

Coronal mass ejections and their sheath regions in interplanetary space

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Differential Emission Measure Analysis of Multiple Structural Components of Coronal Mass Ejections in the Inner Corona

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