the expansion of gaseous sparks.pdf

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1、HomeSearchCollectionsJournalsAboutContactusMyIOPscienceTheExpansionofGaseousSparkChannelsThisarticlehasbeendownloadedfromIOPscience.Pleasescrolldowntoseethefulltextarticle.1950Proc.Phys.Soc.B63649(http://iopscience.iop.org/0370-1301/63/9/302)Viewthetableofcontentsforthisissue

2、,orgotothejournalhomepageformoreDownloaddetails:IPAddress:211.69.195.193Thearticlewasdownloadedon25/10/2011at03:07Pleasenotethattermsandconditionsapply.649TheExpansionofGaseousSparkChannelsBYJ.B.HIGHAMANDJ.M.MEEKDepartmentofElectricalEngineering,UniversityofLiverpoolMS.receiv

3、ed9thMarch1950ABSTRACT.Arotatingmirrorcamerawithatemporalresolutiononthefilmof1.5”ipsec.hasbeenusedtodeterminetherateofexpansionoflonggaseoussparkchannelsduringtheirfirst10psec.ofgrowth.Thesparkchannelsconductedaperiodicimpulsecurrentsintherangeof60to500amp.peak,whichattained

4、theirpeakvaluesinabout1/4psec.anddecayedtohalf-valuein10or28psec.SparkshavebeeninvestigatedInairatatmosphericandreducedpressures,andinnitrogen,oxygenandhydrogenatatmosphericpressure.Themeasuredareasofcrosssectionofthesesparkchannelsbearahearrelationtothepeakcurrents,exceptinh

5、ydrogen,andarelittleinfluencedbytherateofcurrentdecayintherangestudied.Measurementshavealsobeenmadewiththerotatingmlrrorscanninganimageofthesparkacrossaphotomultiplierconnectedtoahighspeedoscillograph;bythismethodadirectrecordisobtainedoftheradiallightdistributionacrossthespa

6、rkchannels.Themechanismofsparkchannelexpansionisdscussed,andestimatesaremadeoftheaverageiondensitiesinsparkchannels.01.INTRODUCTIONNTILthestudiesbyFlowers(1943),whorecordedtheluminousUboundaryofthesparkchannelbyarotating-filmcamera,therehavebeenfewinvestigationsofthecurrentde

7、nsitiesoccurringinsparkchannels,thoughacertainamountofinformationisavailablefromearlierexperimentsbyBeams(1930),LawrenceandDunnington(1930)andDunningtonj1931),allofwhomusedaKerrcelltypeofelectro-opticalshutter.OthermeasurementswithrotatingcamerashavebeenmadebyRaiskij(1940,194

8、8),andmorerecentlybyNorinderandKarsten(1949).Inthepresentinvestigati