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Threshold of parametric instability in the ionospheric heating experiments

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Plasma Science and Technology 2018年第11期20卷 53-60页

作者：王翔周晨刘默然 Farideh HONARY 倪彬彬赵正予 Department of Space Physics School of Electronic Information Wuhan University Department of Physics Lancaster University

Many observations in the ionospheric heating experiment, by a powerful high frequency electromagnetic wave with ordinary polarization launched from a ground-based facility, is attributed to parametric instability （PI）. In this paper, the general dispersion relation and the threshold of the PI excitation in the heating experiment are derived by considering the inhomogeneous spatial distribution of pump wave field. It is shown that the threshold of PI is influenced by the effective electron and ion collision frequencies and the pump wave frequency. Both collision and Landau damping should be considered in the PI calculation. The derived threshold expression has been used to calculate the required threshold for excitation of PI for several ionospheric conditions during heating experiments conducted employing EISCAT high frequency transmitter in TromsФ, Norway, on 2nd October 1998, 8th November 2001, 19th October 2012 and 7th July 2014. The results indicate that the calculated threshold is in good agreement with the experimental observations.

关键词： ionospheric plasma ionospheric modification parametric instability ordinary polarized EM wave

parametric instability of a Liquid Metal Sessile Drop Under a High Frequency Amplitude-Modulate Magnetic Field

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Journal of Iron and Steel Research(International) 2012年第S1期19卷 491-494页

作者： LEI Zuo-sheng ZHANG Li-jie CHEN Chao-yue GUO Jia-hong REN Zhong-ming FAUTRELLE Yves ETAY Jecqueline Shanghai Key Laboratory of Modern Metallurgy and Material Processing Shanghai University Shanghai Institute of Applied Mathematics and Mechanics Shanghai University SIMAP-EPM laboratory Grenoble Institute of Technology/CNRS UMR 526638402 St-Martin d'HeresFrance

The parametric instability behavior of a liquid mercury sessile drop under high frequency Amplitude-Modulate Magnetic Field(AMMF),i.e.a high frequency magnetic field(carder wave)modulated by a low frequency sine wave(modulate wave),is investigated experimentally.The free surface contour of the mercury drop is observed by a CCD camera while varying the frequency and amplitude of the high frequency AMMF.At a given frequency and amplitude,the edge deformations with an azimuthal wave numbers(modes n=3,4,5,6)were excited.

关键词： high frequency Amplitude-Modulate Magnetic Field liquid metal sessile drop parametric instability

On the ponderomotive force and the effect of loss reaction on parametric instability

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Chinese Physics B 2007年第2期16卷 558-563页

作者：吴军吴健 Cesar La Hoz School of Electronic Information Wuhan University Wuhan 430079 China National Key Laboratory of Electromagnetic Environment China Reseaxch Institute of Radiowsve P.O. Box 6301 Beijing 102206 China Department of Physics University of TromsФ Norway

In this paper, the growth rate, ponderomotive force and the exciting condition for parametric instability are derived by considering the loss reaction using a new method. On the basis of the hydrodynamic equations, we take the production and loss reactions in plasma into account to derive the coupling equations for the electron plasma oscillation and ion acoustic oscillation, and obtain the growth rate for the parametric instability, the ponderomotive force and the exciting condition. The result shows that （a） the production reaction has no effect on the parametric instability, and the effect of loss reaction on the parametric instability is a damping one, （b） the more intensive the external field or pump is, the larger the growth rate is, （c） there exist two modes of the ponderomotive force, i.e. the high frequency mode and the low frequency mode, and （d） when ponderomotive force counteracts the damping force, the oscillations become non-damping and non-driving. The ratio of the electron plasma oscillation to ion acoustic oscillation is independent of the loss reaction and the external field.

关键词： parametric instability loss reaction ponderomotive force

parametric decay instabilities of lower hybrid waves on CFETR

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Chinese Physics B 2022年第9期31卷 386-396页

作者：周涛涛项农甘春芸贾国章陈佳乐 Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Centre of Magnetic Fusion Theory Chinese Academy of SciencesHefei 230031China

The lower hybrid current drive is a potential candidate for sustaining plasma current in tokamak steady-state oper-ations,which could be used in China Fusion Engineering Test Reactor(CFETR)with input power up to a few tens of megawatts.Such high input power could trigger the well-known parametric instabilities(PIs)at the plasma edge affect-ing the propagation and absorption of the lower hybrid pump waves.By analytically solving the nonlinear dispersion relation describing PIs,an explicit expression of the PI growth rate is obtained and analyzed in detail.It is found that pressure is the key parameter determining the PI characteristics.Ion sound quasi-mode is the dominant decay channel in the low-pressure regime,while the ion cyclotron quasi-mode(ICQM),as well as its harmonics,becomes dominant in the intermediate regime.In the high-pressure regime,only one mixed channel is found,which is related to Landau damping by free-streaming ions.Analytical expressions of growth rates of these decay channels are also obtained to show the parameter dependence at different pressure limits.The above analytical results are used to estimate the PIs on a typical profile of CFETR,and verified by corresponding numerical calculations.ICQM is found to be the strongest decay channel with a considerable growth rate for CFETR.

关键词： lower hybrid parametric instability CFETR

Ince-Strutt Stability Charts for Ship parametric Roll Resonance in Irregular Waves

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China Ocean Engineering 2017年第4期31卷 447-457页

作者： ZHANG Xiao YANG He-zhen XIAO Fei XU Pei-ji National Key Laboratory on Ship Vibration &Noise China Ship Development and Design Center State Key Laboratory of Ocean Engineering School of Naval Architecture.Ocean and Civil EngineeringShanghai Jiao Tong University School of Civil and Environmental Engineering Nanyang Technological University

Ince-Strutt stability chart of ship parametric roll resonance in irregular waves is conducted and utilized for the exploration of the parametric roll resonance in irregular waves. Ship parametric roll resonance will lead to large amplitude roll motion and even wreck. Firstly, the equation describing the parametric roll resonance in irregular waves is derived according to Grim’s effective theory and the corresponding Ince-Strutt stability charts are obtained. Secondly, the differences of stability charts for the parametric roll resonance in irregular and regular waves are compared. Thirdly, wave phases and peak periods are taken into consideration to obtain a more realistic sea condition. The influence of random wave phases should be taken into consideration when the analyzed points are located near the instability boundary. Stability charts for different wave peak periods are various. Stability charts are helpful for the parameter determination in design stage to better adapt to sailing condition. Last, ship variables are analyzed according to stability charts by a statistical approach. The increase of the metacentric height will help improve ship stability.

关键词： parametric instability parametric rolling multi-frequency irregular waves Ince-Strutt stability chart

Zonal Flows Driven by Small-Scale Drift-Alfven Modes

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Plasma Science and Technology 2011年第5期13卷 523-527页

作者：李德徽周登 Institute of Plasma Physics Chinese Academy of Sciences Center for Magnetic Fusion Theory Chinese Academy of Sciences

Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary modes propagating at both electron and ion diamagnetic drift directions in contrast to the assertion in previous studies that only primary modes propagating in the ion diamagnetic drift directions can drive zonal instabilities. Generally, the growth rate of the driven zonal mode is in the same order as that in previous study. However, different from the previous work, the growth rate is no longer proportional to the difference between the diamagnetic drift frequencies of electrons and ions.

关键词： zonal flow parametric instability drift-Alfven mode diamagnetic drift

Enhancement of wave and acceleration of electron in plasma in the external field

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Frontiers of Electrical and Electronic Engineering in China 2008年第2期3卷 223-226页

作者： Jun WU Jian WU Qiang LI School of Electronic Information Wuhan UniversityWuhan 430079China National Key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave PropagationBeijing 102206China

This paper investigates the enhancement of Langmuir and ion-acoustic wave and the acceleration of the electron in collisionless plasma,in the presence of an external transverse field.Based on hydrodynamic equations,an equation formulizing the parametric instability was derived.Furthermore,the formula for ponderomotive force and the expression that describes the electron acceleration were obtained.The results show that Langmuir and ion-acoustic wave are enhanced and the charged particles can be accelerated by the coupling of wave-wave.In addition,it can be concluded that ponderomotive force,due to the coupling of the external field(pump)to the Langmuir wave(ion-acoustic wave),is the driving force to excite the parametric instability and comprises the high-and low-frequency components.

关键词： parametric instability enhancement of wave acceleration of electron ponderomotive force