Multiscale simulations of type III solar radio emission via beam-driven Langmuir waves

2007 ◽  
Author(s):  
P. A. Robinson ◽  
B. Li ◽  
I. H. Cairns
1994 ◽  
Vol 422 ◽  
pp. 870 ◽  
Author(s):  
P. A. Robinson ◽  
I. H. Cairns ◽  
A. J. Willes

2000 ◽  
Vol 540 (1) ◽  
pp. 572-582 ◽  
Author(s):  
C. S. Wu ◽  
Peter H. Yoon ◽  
Y. Li

2020 ◽  
Author(s):  
Immanuel Christopher Jebaraj ◽  
Jasmina Magdalenic ◽  
Stefaan Poedts

<p>Solar radio emission is studied for many decades and a large number of studies have been dedicated to metric radio emission originating from the low corona. It is generally accepted that solar radio emission  observed at wavelengths below the metric range is produced by the coherent plasma emission mechanism. Fine structures seem to be an intrinsic part of solar radio emission and they are very important for understanding plasma processes in the solar medium. Extensive reporting and number of studies of the metric range fine structures were performed, but studies of fine structures in the interplanetary domain are quite rare. New and advanced ground-based radio imaging spectroscopic techniques (e.g. LOFAR, MWA, etc.,) and space-based observations (Wind/WAVES, STEREO/WAVES A & B, PSP, and SolO in the future) provide a unique opportunity to study radio fine structures observed  all the way from metric to kilometric range.</p><p>Radio signatures of solar eruptive events, such as flares and CMEs, observed in the interplanetary space are mostly confined to type II (radio signatures of magneto-hydrodynamic shock waves), and type III  bursts(electron beams propagating along open and quasi-open magnetic field lines). In this study, we have identified, and analyzed three types of fine structures present within the interplanetary radio bursts. Namely, the striae-like fine structures within type III bursts, continuum-like emission patches, and very slow drifting narrowband structures within type II radio bursts. Since space-based radio observations are limited to dynamic spectra, we use the novel radio triangulation technique employing direction finding measurements from stereoscopic spacecraft (Wind/WAVES, STEREO/WAVES A & B) to obtain the 3D position of the radio emission. The novelty of the technique is that it is not dependent on a density model and in turn can probe the plasma density in the triangulated radio source positions (Magdalenic et al. 2014). Results of the study show that locating the radio source helps not only to understand the generation mechanism of the fine structures but also the ambient plasma conditions such as e.g. electron density. We found that fine structures are associated with complex CME/shock wave structures which interact with the ambient magnetic field structures. We also discuss the possible relationship between the fine structures, the broadband emission they are part of, and the solar eruptive events they are associated with.</p>


1980 ◽  
Vol 86 ◽  
pp. 323-325
Author(s):  
Anthony Achong

The suggestion is made that the excessive time delays between the two components of f-h type III pairs might be partly accounted for by an initial production of the second harmonic only, followed later by the production of both components. The source is assumed to be inside coronal streamers. Theoretical arguments lend some support to the suggestion of a delayed start of the fundamental.


1970 ◽  
Vol 1 (7) ◽  
pp. 313-315 ◽  
Author(s):  
D. J. McLean

For a number of years the occurrence of isolated groups of apparently related type III bursts has been recognized as a common feature of the dynamic spectral records of solar radio emission at metre wavelengths. Interferometer observations supported the simple hypothesis that bursts of a group were usually located in the same position. In this note we report 80 MHz observations made with the Culgoora radioheliograph which show that although the sources of the bursts in a group tend to overlap one another, their centroids may show marked scatter and that their distribution tends to be along narrow lanes across the solar disk. Since the 80 MHz sources occur at heights (≳ 0.6 R⊙) near or above the plasma level, these lanes doubtless reflect some structural feature of the outer corona.


Solar Physics ◽  
2021 ◽  
Vol 296 (3) ◽  
Author(s):  
Mahender Aroori ◽  
Panditi Vemareddy ◽  
Partha Chowdhury ◽  
Ganji Yellaiah

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