Dispersion relation and growth rate in thermal pla

Authors: Samina Dehghanizadeh Shahrooz Saviz

Publish Date: 2015/02/10

Volume: 9, Issue: 2, Pages: 111-118

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Abstract

A theory of relativistic traveling wave tube with magnetized thermal plasmafilled corrugated waveguide with annular electron beam is given The dispersion relation is obtained by linear fluid theory The characteristic of the dispersion relation is obtained by numerical solutions The effect of plasma density corrugated period waveguide radius and plasma thermal effect on the dispersion relation and growth rate are analyzed Some useful results are givenRelativistic traveling wave tube RTWT is an important highpower microwave HPM apparatus which has been developed in the past 20 years 1 2 3 Most of the TWT mathematical analysis has been done by John Robinson Pierce and his colleagues at Bell Labs 4 5 6 and then has been developed by Chu et al 7 8 9 In TWT sinusoidal corrugated slow wave structure SWS is used to reduce the phase velocity of the electromagnetic wave to synchronize it with the electron beam velocity so that a strong interaction between the two can take place 10 11 TWT is extensively applied in satellite and airborne communications radar particle accelerators cyclotron resonance and electronic warfare system The plasma injection to TWT has been studied recently which can increase the growth rate and improve the quality of transmission of electron beam We investigate the effect of thermal plasma and electron beam on the growth rate 12 13 14 15 16 17An analytical and numerical study is made on the dispersion properties of a cylindrical waveguide filled with plasma An electron beam and static external magnetic field are considered as the mechanisms for controlling the field attenuation and possible stability of the waveguide 24 25 26 27 28 29In this paper a RTWT with magnetized thermal plasmafilled corrugated waveguide with annular electron beam is studied The dispersion relation of corrugated waveguide is derived from a solution of the field equations By numerical computation the dispersion characteristics of the RTWT are analyzed in detail in different cases of various geometric parameters of slowwave structureIn Sect 2 the physical model of the RTWT filled with thermal plasma is established in an infinite longitudinal magnetic field In Sect 3 the dispersion relation of the RTWT is derived In Sect 4 the dispersion characteristics of the RTWT are analyzed by numerical computationCylindrical waveguide whose wall radius Rleft z right varies sinusoidal according to the relation 1 h is the corrugation amplitude kappa 0 = 2pi z 0 is the corrugation wave number and z 0 is the length of the corrugation period R 0 is the waveguide radius and k z is the axial wave number

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