Observational evidence for the collapsing Langmuir wave packet in a solar type III radio burst

2013 ◽  
Vol 118 (7) ◽  
pp. 4039-4052 ◽  
Author(s):  
G. Thejappa ◽  
R. J. MacDowall ◽  
M. Bergamo
Keyword(s):  
Wave Packet ◽  
Radio Burst ◽  
Langmuir Wave ◽  
Observational Evidence ◽  
Type Iii ◽  
Solar Type

scholarly journals Observational Evidence for Langmuir Wave Collapse in the Source Region of a Solar Type III Radio Burst

2018 ◽  
Vol 862 (1) ◽  
pp. 75 ◽  
Author(s):  
G. Thejappa ◽  
R. J. MacDowall
Keyword(s):  
Radio Burst ◽  
Source Region ◽  
Langmuir Wave ◽  
Observational Evidence ◽  
Type Iii ◽  
Wave Collapse ◽  
Solar Type

scholarly journals Observational Evidence for the Parametric Decay in a Solar Type III Radio Burst

2020 ◽  
Vol 1620 ◽  
pp. 012023
Author(s):  
G. Thejappa ◽  
R. J. MacDowall
Keyword(s):  
Radio Burst ◽  
Observational Evidence ◽  
Type Iii ◽  
Parametric Decay ◽  
Solar Type

EVIDENCE FOR THE OSCILLATING TWO STREAM INSTABILITY AND SPATIAL COLLAPSE OF LANGMUIR WAVES IN A SOLAR TYPE III RADIO BURST

2012 ◽  
Vol 747 (1) ◽  
pp. L1 ◽  
Author(s):  
G. Thejappa ◽  
R. J. MacDowall ◽  
M. Bergamo ◽  
K. Papadopoulos
Keyword(s):  
Radio Burst ◽  
Langmuir Waves ◽  
Type Iii ◽  
Solar Type ◽  
Stream Instability

Ulysses Observations of Nonlinear Wave-wave Interactions in the Source Regions of Type III Solar Radio Bursts

2000 ◽  
Vol 179 ◽  
pp. 447-450
Author(s):  
G. Thejappa ◽  
R. J. MacDowall
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Langmuir Wave ◽  
Wave Interactions ◽  
Burst Source ◽  
Langmuir Waves ◽  
Type Iii ◽  
Source Regions ◽  
Ion Acoustic ◽  
Solar Type

AbstractThe Ulysses Unified Radio and Plasma Wave Experiment (URAP) has observed Langmuir, ion-acoustic and associated solar type III radio emissions in the interplanetary medium. Bursts of 50–300 Hz (in the spacecraft frame) electric field signals, corresponding to long-wavelength ion-acoustic waves are often observed coincident in time with the most intense Langmuir wave spikes, providing evidence for the electrostatic decay instability. Langmuir waves often occur as envelope solitons, suggesting that strong turbulence processes, such as modulational instability and soliton formation, often coexist with weak turbulence processes, such as electrostatic decay, in a few type III burst source regions.

Detection of Extreme and Exceptional Langmuir Wave Packets in Solar Type III Radio Bursts

2020 ◽  
Vol 125 (6) ◽  
Author(s):  
G. Thejappa ◽  
R. J. MacDowall
Keyword(s):  
Wave Packets ◽  
Langmuir Wave ◽  
Radio Bursts ◽  
Type Iii ◽  
Solar Type

scholarly journals Evidence for Super-Alfvénic Oscillations in Solar Type III Radio Burst Sources

2019 ◽  
Vol 875 (2) ◽  
pp. 98 ◽  
Author(s):  
Atul Mohan ◽  
Surajit Mondal ◽  
Divya Oberoi ◽  
Colin J. Lonsdale
Keyword(s):  
Radio Burst ◽  
Type Iii ◽  
Solar Type

On the solar type III radio burst emission process

1982 ◽  
Vol 256 ◽  
pp. 271 ◽  
Author(s):  
D. G. Wentzel
Keyword(s):  
Radio Burst ◽  
Emission Process ◽  
Type Iii ◽  
Solar Type ◽  
Burst Emission

scholarly journals Electron Beams and Langmuir Turbulence in Solar Type III Radio Bursts Observed in the Interplanetary Medium

1990 ◽  
Vol 142 ◽  
pp. 467-481
Author(s):  
R. P. Lin
Keyword(s):  
Interplanetary Medium ◽  
Electron Beams ◽  
Low Frequency ◽  
Langmuir Wave ◽  
Plasma Waves ◽  
Wave Number ◽  
Langmuir Waves ◽  
Decay Instability ◽  
Type Iii ◽  
Solar Type

The ISEE-3 spacecraft has provided in situ observations of electron beams, plasma waves, and associated solar type III radio emission in the interplanetary medium near 1 AU. These observations show that electron beams are formed by the faster electrons arriving before the slower ones, following an impulsive injection at the Sun. The resulting bump-on-tail in the reduced one-dimensional distribution function, f(v||), is unstable to the growth of electrostatic electron plasma (Langmuir) waves. The Langmuir waves are observed to be highly impulsive in nature. The onset and temporal variations of the observed plasma waves are in good qualitative agreement with the wave growth expected from the evolution of measured f(v||). However, far higher Langmuir wave intensities are predicted than are detected. In addition, the lack of obvious plateauing of the bump-on-tail suggests that the waves have been removed from resonance with the beam electrons by some wave-wave interaction. Bursts of low frequency, 30–300 Hz (in the spacecraft frame) waves are often found coincident in time with the most intense spikes of the Langmuir waves. These low-frequency waves appear to be long-wavelength ion acoustic waves, with wave number approximately equal to the beam-resonant Langmuir wave number. The observations suggest several possible interpretations: modulational instability, electrostatic decay instability, and electromagnetic decay instability; but none of these are fully consistent with the observations. Microstructures, too short in duration to be resolved by present experiments, have been invoked as an explanation of the phenomenon. Experiments are currently being developed to study these processes using fast wave-particle correlation techniques.

Heliograph Observations of both Fast Drift (Type III) and Continuum (Type IV) Solar Emission from the one Source high above the Solar Limb

1978 ◽  
Vol 3 (4) ◽  
pp. 253-256 ◽  
Author(s):  
R. A. Duncan
Keyword(s):  
Langmuir Wave ◽  
Solar Limb ◽  
Continuum Emission ◽  
Type Iii ◽  
Type Iv ◽  
Solar Type ◽  
Fast Drift ◽  
The One ◽  
Wave Conversion ◽  
Late Stages

Many authors (e.g. Magun et al. 1975) have debated the question ‘does solar type IV continuum emission arise through Langmuir wave conversion or through gyro-synchrotron emission?’ Culgoora radio spectrograph and heliograph observations of the late stages of a recent (7 September 1977) type II, IV event showed both type IV* (continuum) and transient type III (electron-beam) emission coming from the same source, high above the solar limb. These observations suggest that this particular type IV continuum arose through a mechanism similar to that of the type III, probably fundamental Langmuir-wave emission, in a corona with a tenfold enhancement of plasma density.

scholarly journals Evidence for four- and three-wave interactions in solar type III radio emissions

2013 ◽  
Vol 31 (8) ◽  
pp. 1417-1428 ◽  
Author(s):  
G. Thejappa ◽  
R. J. MacDowall ◽  
M. Bergamo
Keyword(s):  
Wave Packet ◽  
Second Harmonic ◽  
Wave Packets ◽  
Spectral Peak ◽  
Wave Number ◽  
Radio Bursts ◽  
Langmuir Waves ◽  
Type Iii ◽  
Primary Peak ◽  
Solar Type

Abstract. The high time resolution observations obtained by the STEREO/WAVES experiment show that in the source regions of solar type III radio bursts, Langmuir waves often occur as intense localized wave packets with short durations of only few ms. One of these wave packets shows that it is a three-dimensional field structure with WLneTe ~ 10−3, where WL is the peak energy density, and ne and Te are the electron density and temperature, respectively. For this wave packet, the conditions of the oscillating two-stream instability (OTSI) and supersonic collapse are satisfied within the error range of determination of main parameters. The density cavity, observed during this wave packet indicates that its depth, width and temporal coincidence are consistent with those of a caviton, generated by the ponderomotive force of the collapsing wave packet. The spectrum of each of the parallel and perpendicular components of the wave packet contains a primary peak at fpe, two secondary peaks at fpe ± fS and a low-frequency enhancement below fS, which, as indicated by the frequency and wave number resonance conditions, and the fast Fourier transform (FFT)-based tricoherence spectral peak at (fpe, fpe, fpe + fS, fpe − fS), are coupled to each other by the OTSI type of four-wave interaction (fpe is the local electron plasma frequency and fS is the frequency of ion sound waves). In addition to the primary peak at fpe, each of these spectra also contains a peak at 2fpe, which as indicated by the frequency and wave number resonance conditions, and the wavelet-based bicoherence spectral peak at (fpe, fpe), appears to correspond to the second harmonic electromagnetic waves generated as a result of coalescence of oppositely propagating sidebands excited by the OTSI. Thus, these observations for the first time provide combined evidence that (1) the OTSI and related strong turbulence processes play a significant role in the stabilization of the electron beam, (2) the coalescence of the oppositely propagating up- and down-shifted daughter Langmuir waves excited by the OTSI probably is the emission mechanism of the second harmonic radiation, and (3) the Langmuir collapse follows the route of OTSI in some of the type III radio bursts.

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