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1、IEEETRANSACTIONSONPLASMASCIENCE,VOL.24,NO.1,FEBRUARY1996137ElectricFluctuationsCausedbyGasdynamicTurbulenceinElectric-ArcDevicesY.S.LevitanAbstract-Resultsoftheoreticalinvestigationsonelectricfluc-ForsmallJoule_heatingperturbationsdirectedalongthetuationsinarcdevi
2、cesarepresented.Theseelectricfluctuations,current(forwhichj=const)forexample,inelectricarcsingasflowandinserialMHD-generators,arecausedbygasdynamicturbulence.Correlationsgivingtherelationshipbetweenelectricandgasdynamicfluctua-tionsareobtainedforthesesituations.Es
3、timatesoftheinfluenceofthesecorrelationsontheoveralldeviceparametersaregivenOntheotherhand,forthesameperturbationsdirectedperpen-here.dicularlytothecurrent(forwhichE’=const)+I.INTRODUCTIONq:,=qv-(qv)=032-(.)E22(a’/(.))(a)22.(3)THEappearanceof5lectricfluctuations(p
4、otential(p’,elec-Therefore,from(2)and(3)fora’/(c~)>0JouleheatingtricfieldstrengthE’,currentdensityj’l,Jouleheatingq;,perturbationsdecreasealongthecurrentdirectionandincreaseetc.)duetogasdynamicfluctuations(velocityG’,temperatureperpendicularly.SmallfluctuationsofJ
5、ouleheatingaregivenT’,andpressurep’)isanimportantfeatureofelectric-byarcdeviceswithlowtemperatureandmainlylocalthermalq:,=a’(Z)2+2(o)2.(2)equilibrium(LTE)plasma0,Flo5Pa,TE1eV).Forex-ample,smallgasdynamicfluctuationscauselargefluctuations=(6+26COS$(a)(q2(4)ofconduc
6、tivityandthereforeelectricparameters,ifastrong)dependenceexistsbetweenthemeanconductivityandstatewhere$isananglebetweenthevectorsl?and(2).parameters.Hereisasimpleexample.Ingeneral,fromelectrodynamicequationsforsmallpertur-Asitwasshownearlierexperimentally(see[I]an
7、drefer-bationsencestherein),largeelectricfieldpulsationsandalmostthelackofcurrentdensitypulsationswereobservedinelectric-j”=a’(,??)+(a),?,divj”=0rot2=0(5)arcturbulentplasma.InthiscaseonthebasisofOhm’slawhydrodynamicsapproximationitfollowsforplanewaveperturbations+
8、+;=a2forj”=0k.j’=O,;xl?=0(6)thatthefollowingapproximateformulacanbeobtained:++j’.E‘=0(7)I.?/@)z-&(T’/(T))(1)hereisawavevector.Thenfromthefirstequation(5
