Tracing Electron Beams in the Sun's Corona With Radio Dynamic Imaging Spectroscopy

Bin, Chen; Bastian, T. S.; White, S. M.; Gary, Dale E.; Perley, R. A.; Rupen, M. P.; Carlson, Brent

doi:10.1088/2041-8205/763/1/l21

Cited by 80 publications

(104 citation statements)

References 36 publications

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“…Even in this case, it is likely to be only the harmonic component which may be observed (Chen et al, 2013a). Higher background densities increases the collisional rate and reduces the Langmuir wave growth rate.…”

Section: Reverse and Bi-directional Type III Burstsmentioning

confidence: 89%

A review of solar type III radio bursts

Reid

Ratcliffe

2014

Res. Astron. Astrophys.

333

217

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Solar type III radio bursts are an important diagnostic tool in the understanding of solar accelerated electron beams. They are a signature of propagating beams of nonthermal electrons in the solar atmosphere and the solar system. Consequently, they provide information on electron acceleration and transport, and the conditions of the background ambient plasma they travel through. We review the observational properties of type III bursts with an emphasis on recent results and how each property can help identify attributes of electron beams and the ambient background plasma. We also review some of the theoretical aspects of type III radio bursts and cover a number of numerical efforts that simulate electron beam transport through the solar corona and the heliosphere.

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Section: Reverse and Bi-directional Type III Burstsmentioning

confidence: 89%

A review of solar type III radio bursts

Reid

Ratcliffe

2014

Res. Astron. Astrophys.

333

217

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“…Recent Solar TErrestrial RElations Observatory observations have also revealed trains of plasma blobs within jets in the closed-field corona near active regions (Zhang et al 2016). Using a new imaging technique, Chen et al (2013) analyzed the moving sources of type III radio bursts in an active-region jet. They found multiple reconnection sites within the jet region and filamentary structures in the jet outflow.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Simulations of Tearing and Intermittency in Coronal Jets

Wyper

DeVore

Karpen

et al. 2016

ApJ

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Observations of coronal jets increasingly suggest that local fragmentation and intermittency play an important role in the dynamics of these events. In this work, we investigate this fragmentation in high-resolution simulations of jets in the closed-field corona. We study two realizations of the embedded-bipole model, whereby impulsive helical outflows are driven by reconnection between twisted and untwisted field across the domed fan plane of a magnetic null. We find that the reconnection region fragments following the onset of a tearing-like instability, producing multiple magnetic null points and flux-rope structures within the current layer. The flux ropes formed within the weak-field region in the center of the current layer are associated with "blobs" of density enhancement that become filamentary threads as the flux ropes are ejected from the layer, whereupon new flux ropes form behind them. This repeated formation and ejection of flux ropes provides a natural explanation for the intermittent outflows, bright blobs of emission, and filamentary structure observed in some jets. Additional observational signatures of this process are discussed. Essentially all jet models invoke reconnection between regions of locally closed and locally open field as the jet-generation mechanism. Therefore, we suggest that this repeated tearing process should occur at the separatrix surface between the two flux systems in all jets. A schematic picture of tearing-mediated jet reconnection in three dimensions is outlined.

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“…Jets that are correlated with type III bursts accompany flaring activity that ranges from weak transient brightenings and subflares (Kundu et al 1995b;Raulin et al 1996;Nitta et al 2008) to M-class flares (Krucker et al 2011;Chen et al 2013a). Their dimensions may range from about 10 4 km to more than about 10 5 km.…”

Section: Introductionmentioning

confidence: 99%

A tiny event producing an interplanetary type III burst

Alissandrakis

Nindos

Patsourakos

et al. 2015

A&A

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Aims. We investigate the conditions under which small-scale energy release events in the low corona gave rise to strong interplanetary (IP) type III bursts. Methods. We analyzed observations of three tiny events, detected by the Nançay Radio Heliograph (NRH), two of which produced IP type III bursts. We took advantage of the NRH positioning information and of the high cadence of AIA/SDO data to identify the associated extreme-UV (EUV) emissions. We measured positions and time profiles of the metric and EUV sources. Results. We found that the EUV events that produced IP type III bursts were located near a coronal hole boundary, while the one that did not was located in a closed magnetic field region. In all three cases tiny flaring loops were involved, without any associated mass eruption. In the best observed case, the radio emission at the highest frequency (435 MHz) was displaced by ∼55 with respect to the small flaring loop. The metric type III emission shows a complex structure in space and in time, indicative of multiple electron beams, despite the low intensity of the events. From the combined analysis of dynamic spectra and NRH images, we derived the electron beam velocity as well as the height, ambient plasma temperature, and density at the level of formation of the 160 MHz emission. From the analysis of the differential emission measure derived from the AIA images, we found that the first evidence of energy release was at the footpoints, and this was followed by the development of flaring loops and subsequent cooling. Conclusions. Even small energy release events can accelerate enough electrons to give rise to powerful IP type III bursts. The proximity of the electron acceleration site to open magnetic field lines facilitates the escape of the electrons into the interplanetary space. The offset between the site of energy release and the metric type III location warrants further investigation.

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Tracing Electron Beams in the Sun's Corona With Radio Dynamic Imaging Spectroscopy

Cited by 80 publications

References 36 publications

A review of solar type III radio bursts

A review of solar type III radio bursts

Three-Dimensional Simulations of Tearing and Intermittency in Coronal Jets

A tiny event producing an interplanetary type III burst

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