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Effects of trapped electrons on the ion temperature gradient mode in tokamak plasmas with hollow density profiles

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Plasma Science and Technology 2020年第5期22卷 16-24页

作者： Jingchun LI Jiaqi DONG Songfen LIU School of Physics Nankai UniversityTianjin 300071People's Republic of China University of California IrvineCA 92697United States of America School of Physics and Optoelectronic Technology Dalian University of TechnologyDalian 116024People's Republic of China Southwestern Institute of Physics Chengdu 610041People's Republic of China

The ion temperature gradient(ITG)mode in the presence of impurity ions and trapped electrons(TEs)is numerically investigated in tokamak plasmas with hollow density profiles,using the gyrokinetic integral eigenmode *** is found that in the inverted density plasma,the increase of the ITG enhances the growth rate and frequency of the ITG,and the density gradient plays an important role in the ITG *** weak density gradient situations,the trapped electron effects increase the instability of the ITG,while the impurity has an obviously stabilizing *** the strong density gradient cases,both the impurities and trapped electrons enhance the ITG *** addition,it is shown that the growth rate of the ITG decreases with positive magnetic shear s while the real frequency increases with positive magnetic *** growth rate of the ITG increases with negative magnetic shear s while the real frequency decreases with negative magnetic *** length of the calculated mode structure in the positive and negative magnetic shear intervals is also presented.

关键词： micro-instabilities trapped electrons impurities

Fishbone Instability Excited by Barely trapped electrons

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Chinese Physics Letters 2006年第1期23卷 158-160页

作者：王中天龙永兴董家齐王龙 Fulvio Zonca Southwestern Institute of Physics PO Box 432 Chengdu 610041 Institute of Physics Chinese Academy of Sciences Beijing 100080 Associazione EURATOM-ENEA Sulla Fusione C.P. 65-00044 Frascati Rome Italy

Fishbone instability excited by barely trapped suprathermal electrons （BTSEs） in tokamaks is investigated theoretically. The frequency of the mode is found to close to procession frequency of BTSEs. The growth rate of the mode is much smaller than that of the ideal magnetohytrodynamic （MHD） internal kink mode that is in contrast to the case of trapped ion driven fishbone instability. The analyses also show that spatial density gradient reversal is necessary for the instability. The correlation of the results with experiments is discussed.

关键词： Fishbone Instability trapped electrons

Interplay of parallel electric field and trapped electrons in kappa-Maxwellian auroral plasma for EMEC instability

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Communications in Theoretical Physics 2021年第1期73卷 78-86页

作者： M Nazeer M N S Qureshi C Shen Department of Physics GC UniversityLahore(54000)Pakistan Shenzhen Graduate School HIT CampusUniversity Town of ShenzhenShenzhen 518055China

In this paper,propagation characteristics of electromagnetic electron cyclotron(EMEC)waves based on kappa-Maxwellian distribution have been investigated to invoke the interplay of the electric field parallel to the Earth’s magnetic field and auroral trapped *** dispersion relation for EMEC waves in kappa-Maxwellian distributed plasma has been derived using the contribution of the parallel electric field and trapped electron *** results show that the presence of the electric field has a stimulating effect on growth rate,which is more pronounced at low values of wave *** is also observed that as the threshold value of trapped electron speed is surpassed,it dominates the effect of the parallel electric field and EMEC instability is enhanced *** electric field acts as another source of free energy,and growth can be obtained even in the absence of trapped electron drift speed and for very small values of temperature *** the present study reveals the interplay of the parallel electric field and trapped electron speed on the excitation of EMEC waves in the auroral region.

关键词： EMEC waves kappa-Maxwellian distribution trapped electrons parallel electric field in aurora

Nonlinear Dust Acoustic Waves in a Magnetized Dusty Plasma with trapped and Superthermal electrons

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Plasma Science and Technology 2014年第6期16卷 545-551页

作者： S.Ahmadi ABRISHAMI M.Nouri KADIJANI Islamic Azad University Torbateheydarieh Branch Torbateheydarieh Young Researchers and Elite Club Kashmar Branch Islamic Azad University

In this work, the effects of superthermal and trapped electrons on the oblique propa- gation of nonlinear dust-acoustic waves in a magnetized dusty （complex） plasma are investigated. The dynamic of electrons is simulated by the generalized Lorentzian （k） distribution function （DF）. The dust grains are cold and their dynamics are simulated by hydrodynamic equations. Using the standard reductive perturbation technique （RPT） a nonlinear modified Korteweg-de Vries （mKdV） equation is derived. Two types of solitary waves; fast and slow dust acoustic solitons, exist in this plasma. Calculations reveal that compressive solitary structures are likely to propagate in this plasma where dust grains are negatively （or positively） charged. The properties of dust acoustic solitons （DASs） are also investigated numerically.

关键词： dust acoustic wave trapped electrons superthermal electrons kappa distribution function

Influence of Non-Maxwellian Particles on Dust Acoustic Waves in a Dusty Magnetized Plasma

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Communications in Theoretical Physics 2013年第11期60卷 615-622页

作者： M.Nouri Kadijani H.Zareamoghaddam Young Researchers and Elite Club Kashmar Branch Islamic Azad University

In this paper an investigation into dust acoustic sofitary waves （DASWs） in the presence of superthermM electrons and ions in a magnetized plasma with cold dust gains and trapped electrons is discussed. The dynamic of both electrons and ions is simulated by the generalized Lorentzian （κ） distribution function （DF）. The dust grains are cold and their dynamics are studied by hydrodynamic equations. The basic set of fluid equations is reduced to modified Korteweg-de Vries （mKdV） equation using Reductive Perturbation Theory （RPT）. Two types of solitary waves, fast and slow dust acoustic soliton （DAS） exist in this plasma. Caiculations reveal that compressive solitary structures are possibly propagated in the plasma where dust grains are negatively （or positively） charged. The properties of DASs are also investigated numerically.

关键词： dust acoustic soliton magnetized plasma superthermal electrons and ions trapped electrons