Parametric decay of a whistler wave at the difference frequency of two electromagnetic waves in a plasma

1991 ◽  
Vol 45 (1) ◽  
pp. 115-123 ◽  
Author(s):  
S. Guha ◽  
Ruby Sarkar
Keyword(s):  
Electromagnetic Waves ◽  
Low Frequency ◽  
Whistler Wave ◽  
Difference Frequency ◽  
Lower Hybrid ◽  
Ion Heating ◽  
Lower Hybrid Wave ◽  
Electromagnetic Pump ◽  
The Difference ◽  
Pump Waves

A large-amplitude whistler wave excited at the difference frequency of two high-frequency electromagnetic pump waves is shown to decay parametrically into a lower-hybrid wave (LHW) and a low-frequency ion–Bernstein wave (IBW) in a collisionless magnetized multi-ion-species plasma,. A nonlinear dispersion relation describing this parametric interaction process is derived. The low-frequency ponderomotive force along the direction of the external magnetic field leads to the dominant coupling. Possible applications to ion heating in the ionosphere, in the earth's magnetosphere and in laboratory plasmas are discussed.

scholarly journals Studies of Spectral Broadening of the Lower Hybrid Wave Line in the Current-Drive Regimes and Ion Heating at the FT-2 Tokamak

2021 ◽  
Vol 47 (4) ◽  
pp. 329-336
Author(s):  
V. V. Dyachenko ◽  
A. B. Altukhov ◽  
E. Z. Gusakov ◽  
L. A. Esipov ◽  
A. N. Konovalov ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Low Frequency ◽  
Current Drive ◽  
Lower Hybrid ◽  
Ion Heating ◽  
Lower Hybrid Wave ◽  
Acoustic Instability ◽  
Ion Acoustic ◽  
Lower Hybrid Current Drive ◽  
High Frequency Waves

Abstract The experiments at the FT-2 tokamak are described that were focused on clearing up the role of the parametric decay instabilities in decreasing the generation efficiency of the non-inductive current excited by the electromagnetic waves in the lower hybrid frequency range. The most discussed instability of such kind is the decay of the pump wave into the daughter high-frequency waves and the low-frequency ion–acoustic quasi-modes. The studies performed have shown that, under conditions of the FT-2 experiment, the ion–acoustic instability has no decisive effect on the decrease in the efficiency of the lower hybrid current drive.

Scattering of electromagnetic waves by hybrid waves in a two-electron-temperature plasma

1991 ◽  
Vol 46 (1) ◽  
pp. 99-106 ◽  
Author(s):  
S. K. Sharma ◽  
A. Sudarshan
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Stimulated Scattering ◽  
Coupled Modes ◽  
Temperature Plasma ◽  
Electrostatic Perturbation

In this paper, we use the hydrodynamic approach to study the stimulated scattering of high-frequency electromagnetic waves by a low-frequency electrostatic perturbation that is either an upper- or lower-hybrid wave in a two-electron-temperature plasma. Considering the four-wave interaction between a strong high-frequency pump and the low-frequency electrostatic perturbation (LHW or UHW), we obtain the dispersion relation for the scattered wave, which is then solved to obtain an explicit expression for the growth rate of the coupled modes. For a typical Q-machine plasma, results show that in both cases the growth rate increases with noh/noc. This is in contrast with the results of Guha & Asthana (1989), who predicted that, for scattering by a UHW perturbation, the growth rate should decrease with increasing noh/noc.

DIFFERENCE FREQUENCY HARMONIC ION HEATING

1967 ◽  
Vol 45 (5) ◽  
pp. 1771-1781 ◽  
Author(s):  
C. R. James ◽  
W. B. Thompson
Keyword(s):  
High Frequency ◽  
Collision Frequency ◽  
Difference Frequency ◽  
Fourth Power ◽  
Heating Process ◽  
Ion Heating ◽  
Frequency Signal ◽  
Transverse Waves ◽  
The Difference ◽  
Frequency Harmonic

The heating of a magnetized hot diffuse plasma using the difference frequency signal generated from two high-frequency (35 GHz) transverse waves is examined. The plasma is described by the cold plasma model and a series expansion of harmonics is used to obtain a solution to the equations. It is shown that the energy absorbed by the ions can be made inversely proportional to the collision frequency and the fourth power of the driven frequency and proportional to the fourth power of the driven electric field intensity. An investigation of the sensitivity of the heating process to fluctuations in frequency, density, and d-c. magnetic field is carried out.

Nonlinear decay of a propagating lower-hybrid wave in a plasma

1978 ◽  
Vol 19 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. K. Shukla ◽  
M. A. Mamedow
Keyword(s):  
Electromagnetic Waves ◽  
Fluid Model ◽  
Wave Interaction ◽  
Alfven Wave ◽  
Lower Hybrid ◽  
Threshold Condition ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Two Fluid Model ◽  
Two Fluid

This paper studies the nonlinear coupling between a large amplitude propagating lower-hybrid wave and two electromagnetic waves in a plasma. Using a two-fluid model and Vlasov and Maxwell's equations, we derive a dispersion relation governing this three-wave interaction process. It is shown that a finite wavenumber lower-hybrid pump can decay into a whistler and a kinetic Alfvén wave. Calculations of the threshold condition suggest that this decay process may occur both in the laboratory and in the ionosphere.

Ion heating by lower hybrid wave in the HT-7 tokamak

2001 ◽  
Vol 43 (6) ◽  
pp. 805-811 ◽  
Author(s):  
S X Liu ◽  
B N Wan ◽  
G L Kuang ◽  
X Gao ◽  
L Q Hu ◽  
...  
Keyword(s):  
Lower Hybrid ◽  
Hybrid Wave ◽  
Ion Heating ◽  
Lower Hybrid Wave

On the filamentation of large amplitude lower-hybrid waves

1977 ◽  
Vol 18 (1) ◽  
pp. 165-172 ◽  
Author(s):  
K. H. Spatschek ◽  
P. K. Shukla ◽  
M. Y. Yu
Keyword(s):  
Large Amplitude ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Convective Instabilities ◽  
Modulational Instabilities ◽  
Hybrid Waves ◽  
Lower Hybrid Waves

We consider the propagation of a large-amplitude lower-hybrid wave. Modulational instabilities arising from its interaction with low-frequency electrostatic perturbations are investigated. The growth lengths of the convective instabilities are obtained and compared with previous results for adiabatic perturbations.

Nonlinear transient signal propagation in homogeneous plasma

1982 ◽  
Vol 28 (1) ◽  
pp. 159-175 ◽  
Author(s):  
D. Jovanović ◽  
H. L. Pécseli ◽  
K. Thomsen
Keyword(s):  
Electromagnetic Waves ◽  
Second Harmonic ◽  
Low Frequency ◽  
Signal Propagation ◽  
Transient Signal ◽  
Lower Hybrid ◽  
Homogeneous Plasma ◽  
Natural Modes ◽  
Nonlinear Transient ◽  
Hybrid Waves

The nonlinear transient evolution of a suddenly applied monochromatic wave in a homogeneous plasma is considered, with particular emphasis on the magnetized case, where ordinary and extraordinary electromagnetic waves travelling normal to B are treated. Two important features are described. First, the penetration of the wave front is shown to be accompanied by ‘radiation’ of low-frequency waves, of which ion cyclotron and lower-hybrid waves are considered here. Next, the presence of a nonlinear, second-harmonic precursor is predicted, containing two natural modes of oscillation, one with exactly twice the frequency of the fundamental, and the other a slightly frequency-shifted contribution. The analysis is readily generalized to waves other than those considered here.

scholarly journals Stochastic ion heating by a lower hybrid wave: II

1979 ◽  
Vol 22 (11) ◽  
pp. 2188 ◽  
Author(s):  
Charles F. F. Karney
Keyword(s):  
Lower Hybrid ◽  
Hybrid Wave ◽  
Ion Heating ◽  
Lower Hybrid Wave
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