Parametric excitation of low-frequency convective cell modes by a large amplitude lower-hybrid wave in a plasma

1977 ◽  
Vol 55 (10) ◽  
pp. 866-867 ◽  
Author(s):  
P. K. Shukla ◽  
M. Y. Yu
Keyword(s):  
Growth Rate ◽  
Pump Wave ◽  
Parametric Instability ◽  
Low Frequency ◽  
Convective Cell ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Hybrid Frequency ◽  
Temporal Growth Rate

It is shown that convective cell modes can become purely growing modes in the presence of an intense pump wave near the lower-hybrid frequency. The temporal growth rate and threshold of the parametric instability are presented.

Quasimode decay of a lower-hybrid wave in a two-electron-temperature plasma

1996 ◽  
Vol 56 (2) ◽  
pp. 237-249
Author(s):  
A. Sudarshan ◽  
S. K. Sharma
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
Decay Channel ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Temperature Plasma ◽  
Parametric Decay ◽  
Cylindrical Plasma ◽  
Ion Cyclotron

We study the quasimode decay of a lower-hybrid wave and a damped ion cyclotron wave in a plasma having two kinds of electrons. This decay channel is also investigated for a cylindrical plasma. The behaviour of the threshold and growth rate with variations in Tn/Tc and non/noc are studied, and a comparison is made with previous results. Our results show that the growth rate and the threshold for the onset of parametric decay are influenced by the presence of the second electron species.

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.

scholarly journals Excitation of lower hybrid wave by an ion beam in magnetized plasma

2013 ◽  
Vol 31 (4) ◽  
pp. 747-752 ◽  
Author(s):  
Ved Prakash ◽  
Ruby Gupta ◽  
Suresh C. Sharma ◽  
Vijayshri
Keyword(s):  
Growth Rate ◽  
Ion Beam ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Unstable Wave ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Beam Density

AbstractLower hybrid wave excitation in magnetized plasma by an ion beam via Cerenkov interaction is studied. The lower hybrid modes showed maximum growth rate of the instability when phase velocity of the lower hybrid mode along the magnetic field is comparable to the electron thermal velocity. We have derived the expression for the maximum growth rate and found that the growth rate of the instability increases with beam density. Moreover, the maximum growth rate of the instability scales as the one-third power of the beam density. The real part of the frequency of the unstable wave increases as almost the square root of the beam energy.

Parametric decay instability of an upper-hybrid wave in a two-temperature plasma

1994 ◽  
Vol 51 (2) ◽  
pp. 193-200 ◽  
Author(s):  
S. Konar ◽  
V. Rai
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
Density Ratio ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Hot Electron ◽  
Hybrid Wave ◽  
Temperature Plasma ◽  
Band Frequency ◽  
Parametric Decay

Parametric decay of an upper-hybrid pump into another upper-hybrid wave and a low-frequency lower-hybrid mode is considered in a two-electron temperature plasma. Expressions for the nonlinear dispersion relation and growth rate are obtained. It is found that the growth rate is quite sensitive to the hot-electron temperature and the density ratio of the hot and the cold components only when the side-band frequency is close to the second or third harmonic of the cyclotron frequency. The relevance of our investigation to Q machines and the ELMO bumpy torus is pointed out.

Anomalous transport and anomalous heating due to lower-hybrid wave fields

1988 ◽  
Vol 39 (3) ◽  
pp. 447-474 ◽  
Author(s):  
M. Krämer ◽  
N. Sollich ◽  
J. Dietrich
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Field Energy ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Heating Rates ◽  
Lower Hybrid Wave ◽  
Drift Wave Turbulence ◽  
Frequency Fluctuations ◽  
High Frequency Waves

The microscopic and macroscopic behaviours of a linear reflex discharge in the presence of low-frequency turbulence are investigated under the action of moderate lower-hybrid wave power. The frequency and wavenumber spectra of both the low-frequency fluctuations and the high-frequency waves are measured using a correlation-analysis technique with two probes. The low-frequency fluctuations may be attributed to drift-wave turbulence. The fluctuation level is raised when RF power is coupled to the plasma, thus leading to considerably enhanced radial transport. The coupling between low-frequency fluctuations and high-frequency waves can be seen clearly from the spectra. The high-frequency wavenumber spectra measured inside the antenna are in reasonable agreement with the lower-hybrid wave dispersion. However, the wavenumbers observed in the lower-hybrid resonance region outside the antenna are – in contrast with expectation – not larger than in the plasma edge region. From the electric-field energy-density spectra and from measurements of the density and the temperatures, a detailed energy balance can be performed. The calculated heating rates are anomalously large for both the electrons and the ions. The absorption processes, relevant for the present experiment, are discussed.

Parametric decay of an upper-hybrid wave in a plasma cylinder

1997 ◽  
Vol 58 (2) ◽  
pp. 277-285
Author(s):  
S. C. SHARMA
Keyword(s):  
Growth Rate ◽  
Nonlinear Interaction ◽  
Perturbation Technique ◽  
Wave Functions ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Plasma Cylinder ◽  
Coupled Mode ◽  
Parametric Decay

A large-amplitude upper-hybrid wave in a plasma cylinder is susceptible to parametric decay into a lower-hybrid wave and an upper-hybrid wave. The perpendicular and parallel motions of electrons play equally important roles in the nonlinear interaction. The coupled-mode equations are solved using a perturbation technique. The growth rate of the instability is less sensitive to the radial mode number of the sideband. However, for higher-order radial modes it falls off as the overlap of the interacting wave functions decreases.

Generation of the kinetic alfven wave and lower hybrid wave in space plasma

2001 ◽  
Vol 7 (2s) ◽  
pp. 59-66
Author(s):  
A.K. Yukhimuk ◽  
◽  
V.N. Fedun ◽  
Yu. Voitenko ◽  
E.K. Sirenko ◽  
...  
Keyword(s):  
Space Plasma ◽  
Alfven Wave ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Kinetic Alfvén Wave ◽  
Kinetic Alfven Wave

X-ray Measurements during Plasma Current Start-up Experiments using the Lower Hybrid Wave on the TST-2 Spherical Tokamak

2012 ◽  
Vol 132 (7) ◽  
pp. 485-489 ◽  
Author(s):  
Takuma Wakatsuki ◽  
Akira Ejiri ◽  
Hidetoshi Kakuda ◽  
Yuichi Takase ◽  
Takanori Ambo ◽  
...  
Keyword(s):  
Lower Hybrid ◽  
Spherical Tokamak ◽  
Plasma Current ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
X Ray ◽  
Start Up

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.

High field side lower hybrid wave launch for steady state plasma sustainment

2018 ◽  
Vol 58 (12) ◽  
pp. 126032 ◽  
Author(s):  
P.T. Bonoli ◽  
G.M. Wallace ◽  
S. Shiraiwa ◽  
S.G. Baek ◽  
J. Doody ◽  
...  
Keyword(s):  
Steady State ◽  
High Field ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
State Plasma
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