Electron Acceleration in Reconnecting Current Sheets

Wood, Paul; Neukirch, T.

doi:10.1007/s11207-005-5686-y

Cited by 94 publications

(89 citation statements)

References 43 publications

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“…It has been contended by Moore et al (1995) and Lin et al (2009) that the width of these regions is ≈0.1 to 1 Mm. Narrower current sheets, as proposed by Wood and Neukirch (2005), would result in even smaller diffusion time scales. Clearly, unlike the global magnetic diffusion time-scale of several months, the diffu-sion time scale in currents sheets is very small (τ d ≈ 1 s to 10 min).…”

Section: Energy Releasementioning

confidence: 89%

The magnetic field in the solar atmosphere

Wiegelmann

Thalmann

Solanki

2014

Astron Astrophys Rev

176

125

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This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.

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Section: Energy Releasementioning

confidence: 89%

The magnetic field in the solar atmosphere

Wiegelmann

Thalmann

Solanki

2014

Astron Astrophys Rev

176

125

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“…First of all, a long and thick CS is favorable for charged particle acceleration. Currently, the scale of the CS is small, of order a few meters thick and tens of meters long, in existing models of the particle acceleration in the CS (e.g., see Litvinenko 1996; Wood and Neukirch 2005;Dauphin et al 2007). Particles cannot remain long in such a CS, say ∼ 10 −5 s for electrons and < 10 −3 s for protons, so the efficiency of acceleration is fairly low and it is difficult to fulfill the requirement for the rate of production of energetic electrons (> 10 keV, 10 35 s −1 ) in a typical solar flare (Martens 1988).…”

Section: Discussionmentioning

confidence: 99%

Review on Current Sheets in CME Development: Theories and Observations

et al. 2015

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We introduce how the catastrophe model for solar eruptions predicted the formation and development of the long current sheet (CS) and how the observations were used to recognize the CS at the place where the CS is presumably located. Then, we discuss the direct measurement of the CS region thickness by studying the brightness distribution of the CS region at different wavelengths. The thickness ranges from 10 4 km to about 10 5 km at heights between 0.27 and 1.16 R from the solar surface. But the traditional theory indicates that the CS is as thin as the proton Larmor radius, which is of order tens of meters in the corona. We look into the huge difference in the thickness between observations and theoretical expectations. The possible impacts that affect measurements and results are studied, and physical causes leading to a thick CS region in which reconnection can still occur at a reasonably fast rate are analyzed. Studies in both theories and observations suggest that the difference between the true value and the apparent value of the CS thickness is not significant as long as the CS could be recognised in observations. We review observations that show complex structures and flows inside the CS region and present recent numerical modelling results on some aspects of these structures. Both observations and numerical experiments indicate that the downward reconnection outflows are usually slower than the upward ones in the same eruptive event. Numerical simulations show that the complex structure inside CS and its temporal behavior as a result of turbulence and the Petschek-type slow-mode shock could probably account for the thick CS and fast reconnection. But whether the CS itself is that thick still remains unknown since, for the time being, we cannot measure the electric current directly in that region. We also review the most recent laboratory experiments of reconnection driven by energetic laser beams, and discuss some important topics for future works.

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“…The ray is as wide as tens to hundreds of kilometers, wider by several orders of magnitude than that predicted by classical plasma theory [113,114]. Broadening mechanisms related to turbulent reconnections associated with tearing mode instabilities or time-dependent Petschek reconnections have been proposed [115].…”

Section: Studies On Magnetic Islands Of Reconnections Along the Cme Cmentioning

confidence: 92%

A review of recent studies on coronal dynamics: Streamers, coronal mass ejections, and their interactions

Chen

2013

Chin. Sci. Bull.

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In this article I present a review of recent studies on coronal dynamics, including research progresses on the physics of coronal streamers that are the largest structure in the corona, physics of coronal mass ejections (CMEs) that may cause a global disturbance to the corona, as well as physics of CME-streamer interactions. The following topics will be discussed in depth: (1) acceleration of the slow wind flowing around the streamer considering the effect of magnetic flux tube curvature; (2) physical mechanism accounting for persistent releases of streamer blobs and diagnostic results on the temporal variability of the slow wind speed with such events; (3) force balance analysis and energy release mechanism of CMEs with a flux rope magnetohydrodynamic model; (4) statistical studies on magnetic islands along the coronal-ray structure behind a CME and the first observation of magnetic island coalescence with associated electron acceleration; and (5) white light and radio manifestations of CME-streamer interactions. These studies shed new light on the physics of coronal streamers, the acceleration of the slow wind, the physics of solar eruptions, the physics of magnetic reconnection and associated electron acceleration, the large-scale coronal wave phenomenon, as well as the physics accounting for CME shock-induced type II radio bursts. solar wind, coronal streamer, coronal mass ejection, solar radio burst, magnetic reconnection Citation:Chen Y. A review of recent studies on coronal dynamics: Streamers, coronal mass ejections, and their interactions.

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Electron Acceleration in Reconnecting Current Sheets

Cited by 94 publications

References 43 publications

The magnetic field in the solar atmosphere

The magnetic field in the solar atmosphere

Review on Current Sheets in CME Development: Theories and Observations

A review of recent studies on coronal dynamics: Streamers, coronal mass ejections, and their interactions

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