学科分类
/ 1
17 个结果
  • 简介:NonlinearMHDKelvin-Helmholtz(K-H)instabilityinapipeistreatedwiththederiva-tiveexpansionmethodinthepresentpaperThelinearstabilityproblemwasdiscussedinthepastbyChandrasekhar(1961)andXuetal.(1981).Nagano(1979)discussedthenonlinearMHDK-Hinstabilitywithinfinitedepth.Heusedthesingularperturbationmethodandextrapolatedtheob-tainedsecondordermodifierofamplitudevs.frequencytoseekthenonlineareffectontheinstabilitygrowthrateγ.However,inourview,suchanextrapolationisinappropriate.Becausewhentheinstabili-tysetsin,thegrowthratesofhigher,ordertermsontherighthandsideofequationswillexceedthecor-respondingsecularproducingterms,sotheexpansionwillstillbecomemeaninglessevenifthesecularproducingtermsareeliminated.Mathematicallyspeaking,it’simpossibletoderiveformula(39)whenγ02isnegativeinNagano’spaper.Moreover,evenasearlyasγ02→O+,theexpansionbe-comesinvalidbecausethe2ndordermodifierγ2(inhisformula(56))tendstoinfinity.Thisweak-nessisremovedinthispaper,andtheresultisextendedtothecaseofapipewithfinitedepth.

  • 标签: NONLINEAR MHD INSTABILITY KELVIN-HELMHOLTZ INSTABILITY MHD
  • 简介:本文根据I型彗尾的背景材料,分析了MHD波的色散关系,探讨了螺旋波的稳定性及其演变的特征。根据初始条件的不同,有的彗尾中可以产生稳定的螺旋波,有的则不然,只能是浑云状态。文章给出了理论推演,列出了观测结果,理论和观测能较好地符合。可进一步结合Hale-Bopp彗星的观测,进行对比和检验。

  • 标签: 彗尾 太阳风 螺旋波 等离子体不稳定性
  • 简介:Non-lineardevelopmentofdoubletearingmodesinducedbyelectronviscosityisnumericallysimulated.MHDflowlayersaredemonstratedtomergeinthedevelopmentofthemodes.Theshearedflowsareshowntoliejustattheboundariesofthemagneticislands,andtohavesuffcientlevelsrequiredforinternaltransportbarrier(ITB)formation.PossiblecorrelationbetweenthelayerformationandtriggeringofexperimentallyobservedITBs,preferentiallyformedinproximitiesofrationalfluxsurfacesoflowsafetyfactors,isdiscussed.

  • 标签: MHD流层 边界 托卡马克等离子体 传送屏障 电子粘性
  • 简介:稳定的laminar流动的问题的一个近似答案一粘滞在一张拉长的表上的不可压缩的电子上进行的液体被介绍。途径基于拉长流动问题的变量然后使用最少的广场方法最小化一个微分方程的剩余的想法。流动特征上的磁场的效果与Hartman数字的不同价值通过数字计算被表明。

  • 标签: < KEYWORDS
  • 简介:Anewmethodforconstructingthesymmetricformforthehyperbolicsystemsisintroduced.ThenanewsymmetricformoftheequationsofMHDtransverseflowisconstructedbyaddinganadditionalequation.Withthisnewform,weobtainthelocalexistenceofsmoothsolutionincludingthecasethattheinitialdensitymaytendtothevacuumstateatinfinity.Furthermore,theuniformlyaprioriestimationfortheclassicalsolutionsisestablishedandtheglobalsmoothsolutionsforakindofinitialdataareobtained.

  • 标签: MHD横向流 完整经典解 相称性 双曲线系统
  • 简介:Inthispaper,weconsidertheblow-upofsmoothsolutionstothe3DidealMHDequations.Let(u,b)beasmoothsolutionin(0,T).Itisprovedthatthesolution(u,b)canbeextendedaftert=Tif(↓Δ×u,↓Δ×b)∈L^1(0,T;B∞,∞^0).ThisisanimprovementoftheresultgivenbyCaflisch,Klapper,andSteele.

  • 标签: MHD方程 磁场 流速 比绍夫空间 光滑解 偏微分方程
  • 简介:Inordertosolvethemagneto-hydrodyna-mics(MHD)problems,itisneccessarytocombineMaxwell'sequationswithfluidmechanicsequations.But,underthefirstorderapproximationthemasspointmotivationequationsandelectromagneticbasiclawsare

  • 标签: MHD 不稳定性 喷气流 流体力学 麦克斯韦方程
  • 简介:Inlostpaperofmagneto-hydrodynamicinstabilityanalysisofliquidmetalfreesurfacejetflow(PartⅠ),themagneto-hydrodynamicinstabilitywasanalyzedforthejetflowinatransversenon-uniformmagneticfield,BT.But,asallknown,fortherealconditionsofliquidmetallimiter-divertorplasma-facingcomponentsareintoroidalandpoloidalfields.So,wetrytoanalyzethemagneto-hydrodynamicinstabilityofthejetflow(herebyonlyforcircularshapecrosssectionjetflow)inthezoneofnon-uniformmagneticfields,

  • 标签: 自由表面射流 磁流体动力学 不稳定性 磁聚变 液态金属偏滤器