Parametric decay of wide band Langmuir wave spectra

2016 ◽  
Vol 82 (6) ◽  
Author(s):  
Mitsuo Kono ◽  
Hans L. Pécseli
Keyword(s):  
Continuous Wave ◽  
Modulational Instability ◽  
Wave Spectrum ◽  
Langmuir Wave ◽  
Single Mode ◽  
Wide Band ◽  
Wave Spectra ◽  
Langmuir Waves ◽  
Parametric Decay ◽  
Wave Models

Previous results obtained for modulational instability of a Langmuir wave spectrum are extended to account also for the Langmuir wave decay. The general model is tested by considering first the parametric decay of single-mode Langmuir waves, and also two-wave models, where several combinations are considered: one wave is modulationally unstable, another decay unstable and one where both waves are unstable with respect to decay. For the general case with continuous wave spectra it is found that distribution of the Langmuir wave energy over a wide wavenumber band reduces the decay rate when the correlation length for the spectrum becomes comparable to the wavelength of the most unstable sound wave among the possible decay products.

scholarly journals Stability of electron wave spectra in weakly magnetized plasmas

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
M. Kono ◽  
H. L. Pécseli
Keyword(s):  
Continuous Wave ◽  
Wave Spectrum ◽  
Spectral Width ◽  
Plasma Waves ◽  
Electron Plasma ◽  
Analytical Models ◽  
Magnetized Plasmas ◽  
Wave Spectra ◽  
Weakly Nonlinear ◽  
Modulational Instabilities

Analytical models for nonlinear electron plasma waves in weakly magnetized plasmas are developed for single as well as multi-mode conditions, with continuous wave spectra being a limiting case. The conditions for wave decay as well as modulational instabilities are analysed. Our results demonstrate that slow or nearly stationary plasma density variations can be found for weakly magnetized plasmas even for weakly nonlinear electron plasma waves without involving cavitation of large amplitude plasma waves. A reduction of the growth rates for decay as well as modulational instabilities are found when the spectral width of the wave spectrum is increased. Some of our results are relevant for the interpretation of the nonlinearly enhanced ion acoustic lines often observed in non-equilibrium ionospheres.

scholarly journals Modulational Interactions of Two Monochromatic Waves and Packets of Random Waves

1994 ◽  
Vol 47 (4) ◽  
pp. 375 ◽  
Author(s):  
SV Vladimirov ◽  
SI Popel
Keyword(s):  
Modulational Instability ◽  
Single Mode ◽  
Maximum Effect ◽  
Random Wave ◽  
Random Waves ◽  
Third Order ◽  
Langmuir Waves ◽  
Coupled Equations ◽  
Instability Development ◽  
Field Correlation

The modulational instability of Langmuir waves in unmagnetised plasmas is reviewed for the cases when a pump consist of two monochromatic or a large number of random modes. It is demonstrated that the correct theory for the modulational instability operates with 'renormalised' equations for the linear dielectric function as well as for the effective third-order plasma response. This renormalisation is due to so-called interference terms. The appearance of interference terms is a specific feature of the multi-mode modulational instability in comparison with the well-known instability of a single mode. All calculations use a simple and universal formalism including new methods developed for description of the modulational effects in arbitrary media. The modulational instability of two pump Langmuir modes is considered for the case of comparatively small instability rates, when 'renormalised' expressions for linear and nonlinear plasma polarisation responses provide the maximum effect on the instability development. For instabilities of the broad spectra of random waves, the integral equations are presented for perturbations of wave field correlation functions. In the description of the modulational instability of random wave packets these equations play the same role as the set of coupled equations for the fields of modulational perturbations in the case of two monochromatic pumps. Rates and thresholds of the instabilities are found in various limits.

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.

Collisional drift waves in the presences of coherent ion acoustic or Langmuir waves

1971 ◽  
Vol 6 (3) ◽  
pp. 527-540 ◽  
Author(s):  
M. Dobrowolny ◽  
P. Negrini
Keyword(s):  
Acoustic Wave ◽  
Wave Spectrum ◽  
Langmuir Wave ◽  
Drift Waves ◽  
Langmuir Waves ◽  
Ion Acoustic Wave ◽  
Linear Interaction ◽  
Drift Wave ◽  
Ion Acoustic ◽  
The Stability

The dispersion properties of drift waves in a low β weakly collisional plasma, in the presence of ion acoustic or Langmuir waves parallel to magnetic lines, are investigated. It is shown that the non-linear interaction with an ion acoustic wave mainly leads to a shift of the drift wave spectrum towards lower frequencies (and only under very particular conditions affects the stability of the drift wave). The interaction with a Langmuir wave, on the contrary, yields a contribution to the imaginary part of the frequency. The conditions under which this stabilizes unstable drift modes are derived and discussed.

scholarly journals On the influence of Langmuir wave spectra on the spectra of electromagnetic waves generated in solar plasma with double plasma frequency

2021 ◽  
Vol 503 (4) ◽  
pp. 5740-5745
Author(s):  
Igor V Kudryavtsev ◽  
T I Kaltman
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Langmuir Wave ◽  
Wave Spectra ◽  
Langmuir Waves ◽  
Solar Plasma ◽  
Transverse Electromagnetic

ABSTRACT In this paper, we consider the spectral dependences of transverse electromagnetic waves generated in solar plasma at the coalescence of Langmuir waves. It is shown that different spectra of Langmuir waves lead to characteristic types of transversal electromagnetic wave spectra, what makes it possible to diagnose the features of the spectra of Langmuir waves generated in solar plasma.

Modulational stability of electron plasma wave spectra

2014 ◽  
Vol 80 (5) ◽  
pp. 745-769 ◽  
Author(s):  
H. L. Pécseli
Keyword(s):  
Modulational Instability ◽  
Power Spectra ◽  
Langmuir Wave ◽  
Spectral Width ◽  
Electron Plasma ◽  
Analytical Models ◽  
Wave Spectra ◽  
Root Mean Square Amplitude ◽  
Weakly Nonlinear ◽  
Average Dispersion

Analytical models for weakly nonlinear electron plasma waves are considered in order to obtain dynamic equations for the space-time evolution of their local power spectra. The model contains the wave kinetic equation as a limiting case for slow, long wavelength modulations. It is demonstrated that a finite spectral width in wavenumbers has a stabilizing effect on the modulational instability. The results invite a simple heuristic relation between the spectral width and the root-mean-square amplitude of stable stationary turbulent Langmuir wave spectra. A non-local average dispersion relation is derived as a limiting form by using the formalism developed for the spectral dynamics.

A High Speed and Ultra Long-Haul Radio-Over-Fiber System Employing Dual Photoelectric Arms Coherent Modulation and Optical Duo-Binary Coding

2014 ◽  
Vol 988 ◽  
pp. 544-547
Author(s):  
Guang Li
Keyword(s):  
High Speed ◽  
Continuous Wave ◽  
Single Mode ◽  
Fiber Amplifier ◽  
Radio Over Fiber ◽  
Laser Source ◽  
Signal Spectrum ◽  
Fiber System ◽  
Binary Coding ◽  
Coherent Modulation

A novel high speed and ultra long-haul radio-over-fiber (ROF) system based on Dual Photoelectric Arms Coherent Modulation (DPACM) and Optical Duo-Binary Coding (ODBC) is proposed, and demonstrated. The signal spectrum bandwidth, generated by ODBC based on the first order DPACM, is half of non-return-to-zero (NRZ ) signal spectrum bandwidth. The secondary order DPACM generates a 40-GHz Millimeter-wave (mm-wave) that is transmitted over fiber (ROF). The simulation results show that, the bit rate can be up to 40 Gbps and the transmission distance is over 1500 Km, based on the ROF system with a 0 dBm continuous-wave laser source, multiple stages Er-Doped Fiber Amplifier (EDFA), a standard single mode fiber (SSMF) with a dispersion of 17 ps/nm/Km and a attenuation of 0.2 dB/Km.

scholarly journals Coherent control of acoustic phonons in a silica fiber using a multi-GHz optical frequency comb

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mamoru Endo ◽  
Shota Kimura ◽  
Shuntaro Tani ◽  
Yohei Kobayashi
Keyword(s):  
Coherent Control ◽  
Continuous Wave ◽  
Frequency Comb ◽  
Effective Interaction ◽  
Interaction Strength ◽  
Single Mode ◽  
Optical Frequency Comb ◽  
Material Structure ◽  
Optical Frequency ◽  
Acoustic Phonons

AbstractMulti-gigahertz mechanical vibrations that stem from interactions between light fields and matter—known as acoustic phonons—have long been a subject of research. In recent years, specially designed functional devices have been developed to enhance the strength of the light-matter interactions because excitation of acoustic phonons using a continuous-wave laser alone is insufficient. However, the strength of the interaction cannot be controlled appropriately or instantly using these structurally-dependent enhancements. Here we show a technique to control the effective interaction strength that does not operate via the material structure in the spatial domain; instead, the method operates through the structure of the light in the time domain. The effective excitation and coherent control of acoustic phonons in a single-mode fiber using an optical frequency comb that is performed by tailoring the optical pulse train. This work represents an important step towards comb-matter interactions.

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