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.

scholarly journals Mode Conversion and Reflection of Langmuir Waves in an Inhomogeneous Solar Wind

2001 ◽  
Vol 18 (4) ◽  
pp. 355-360 ◽  
Author(s):  
A. J. Willes ◽  
Iver H. Cairns
Keyword(s):  
Solar Wind ◽  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Mode Conversion ◽  
Langmuir Wave ◽  
Solar Wind Plasma ◽  
Langmuir Waves ◽  
Transverse Electromagnetic ◽  
Solar Wind Parameters ◽  
Conversion Efficiencies

AbstractBeam-driven Langmuir waves in the solar wind are generated just above the electron plasma frequency, which fluctuates in the inhomogeneous solar wind plasma. Consequently, propagating Langmuir waves encounter regions in which the wave frequency is less than the local plasma frequency, where they can be reflected, mode converted to transverse electromagnetic waves, and trapped in density wells. The aim here is to investigate Langmuir wave reflection and mode conversion at a linear density gradient for typical solar wind parameters. It is shown that higher mode conversion efficiencies are possible than previously calculated, but that mode conversion occurs in a smaller region of parameter space. In addition, the possibility of detecting mode conversion with in situ spacecraft Langmuir wave observations is discussed.

Excitation of Electrostatic Fields in a Plasma by Transverse Electromagnetic Waves

1971 ◽  
Vol 49 (24) ◽  
pp. 3221-3226 ◽  
Author(s):  
M. P. Bachynski ◽  
B. W. Gibbs
Keyword(s):  
Electromagnetic Wave ◽  
Incident Wave ◽  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Incident Field ◽  
Isotropic Plasma ◽  
Electrostatic Fields ◽  
Plane Transverse ◽  
Dielectric Coefficient ◽  
Transverse Electromagnetic

An experiment has been conducted in which a plane transverse electromagnetic wave is incident from free space on a layer of isotropic plasma at small angles (0–12°) of incidence. Strong longitudinal electrostatic fields are observed within the plasma in the regions where the radian frequency of the incident wave equals the plasma frequency when the electric vector of the incident field is in the plane of incidence. Only weak longitudinal electrostatic fields are observed if the incident electric field is perpendicular to the plane of incidence. The observed phenomenon appears consistent with the field growth in a region where the dielectric coefficient of a plasma becomes zero.

Rayleigh surface waves along the boundary between a plasma and a metallic screen

1993 ◽  
Vol 49 (2) ◽  
pp. 227-235 ◽  
Author(s):  
S. T. Ivanov ◽  
K. M. Ivanova ◽  
E. G. Alexov
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Surface Waves ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Cyclotron Frequency ◽  
Plasma Frequency ◽  
Magnetoactive Plasma ◽  
Rayleigh Surface Waves ◽  
The Waves

Electromagnetic wave propagation along the interface between a magnetoactive plasma and a metallic screen is investigated analytically and numerically. It is shown that the waves have a Rayleigh character: they are superpositions of two partial waves. It is concluded that electromagnetic waves propagate only at frequencies lower than min (ωp, ωc), where ωpis the plasma frequency and ωcis the cyclotron frequency. The field topology is found, and the physical character of the waves is discussed.

Multiple-Frequency Measurements of a Flare Continuum Event

1982 ◽  
Vol 4 (4) ◽  
pp. 389-392 ◽  
Author(s):  
R.D. Robinson
Keyword(s):  
Solar Flares ◽  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Close Association ◽  
Type Ii ◽  
Multiple Frequency ◽  
Langmuir Waves ◽  
Long Duration ◽  
Type Ii Radio Bursts ◽  
The Continuum

A type of metre-wavelength continuum is observed in close association with solar flares and Type II radio bursts. This continuum is stationary in position, often intense, of a long duration (occasionally lasting well over an hour) and highly polarized (Robinson and Smerd 1975; Robinson 1978). It is thought to be produced by the conversion of Langmuir waves to electromagnetic waves near the local plasma frequency. Because of its close association with Type II bursts, the class has been designated as Type II related flare continuum, or FCII. In this paper I examine a particularly clear example of such an event, with emphasis on the relation between the Type II and the start of the continuum.

scholarly journals Nonlinear generation of the fundamental radiation in plasmas: the influence of induced ion-acoustic and Langmuir waves

1992 ◽  
Vol 48 (1) ◽  
pp. 71-84 ◽  
Author(s):  
F. B. Rizzato ◽  
A. C.-L. Chian
Keyword(s):  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Low Frequency ◽  
Emission Mechanism ◽  
Langmuir Waves ◽  
Laboratory Plasmas ◽  
Ion Acoustic ◽  
Present Context ◽  
Fundamental Radiation ◽  
Stream Instability

A nonlinear emission mechanism of electromagnetic waves at the fundamental plasma frequency has been examined by Chian & Alves. This mechanism is based on the electromagnetic oscillating two-stream instability driven by two oppositely propagating Langmuir waves. The excitation of the electromagnetic oscillating two-stream instability is due to nonlinear wave–wave coupling involving Langmuir waves, low-frequency density waves and electromagnetic waves. In this paper the Chian & Alves model is improved using the generalized Zakharov equations. Attention is directed toward the influence of induced low-frequency and Langmuir waves on the properties of the electromagnetic oscillating two-stream instability. Presumably, the properties derived in the present context may be relevant to both space and laboratory plasmas.

scholarly journals Kinetic Simulations of Type II Radio Burst Emission Processes

2010 ◽  
Vol 6 (S274) ◽  
pp. 470-472 ◽  
Author(s):  
Urs Ganse ◽  
Felix Spanier ◽  
Rami Vainio
Keyword(s):  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Electron Beams ◽  
Langmuir Wave ◽  
Wave Interaction ◽  
Type Ii ◽  
Wave Excitation ◽  
Wave Processes ◽  
Particle In Cell ◽  
Theoretical Predictions

AbstractUsing a fully relativistic, 3D particle in cell code we have studied Langmuir- and electromagnetic wave processes in a CME foreshock plasma with counterstreaming electron beams. Langmuir wave excitation in resonance with the plasma frequency is observed, with timescales in accordance with theoretical predictions. However, no three wave interaction leading to emission of electromagnetic waves were detectable within the timeframe of our simulations.

Solar Second Harmonic Plasma Emission and the Head-on Approximation

1995 ◽  
Vol 12 (2) ◽  
pp. 197-201 ◽  
Author(s):  
A. J. Willes ◽  
P. A. Robinson ◽  
D. B. Melrose
Keyword(s):  
Narrow Band ◽  
Plasma Frequency ◽  
Second Harmonic ◽  
Langmuir Wave ◽  
Radio Bursts ◽  
Type Ii ◽  
Coalescence Process ◽  
Solar Radio Bursts ◽  
Langmuir Waves ◽  
Band Spectra

AbstractThe coalescence of two Langmuir waves, L and L′, produces emission at twice the plasma frequency in type II and type III solar radio bursts. The analysis of the coalescence process is usually simplified by assuming the head-on approximation, where the wavevectors of the coalescing waves satisfy kL′ ≈ −kL, corresponding to the two Langmuir waves meeting head on. However, this is not always a valid approximation, particularly when the peak of the Langmuir spectrum lies at small wavenumbers, for narrow band spectra, and for spectra with broad angular ranges. Realistic Langmuir wave spectra are used to investigate the effects of relaxing the head-on approximation.

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.

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

Sign in / Sign up

Export Citation Format

Share Document