简介：

简介：Thevisibleandnear-UVemissionspectroscopyofmethane(CH4)inducedbyafemtosecondintenselaserfield(800nm,40fs,1014W∕cm2)isstudied.BymeasuringthedecayprofilesoftheneutralfragmentproductCH(A2Δ→X2Π),tworeactionpathways,i.e.,theelectron-ionrecombinationthroughe-tCHt4andthedirectdisintegrationofCHt4arefoundtoberesponsibleforpopulatingtheelectronicexcitedstatesoftheneutralfragmentproductCH,whichgivesrisetothephotoemissions.Ourresultsprovidecomplementaryinformationonpreviousunderstandingofthestrong-field-inducedphotoemissionmechanismofCH4throughneutraldissociationofsuperexcitedstates.

简介：Anionbeamhastheuniquefeatureofbeingabletodeposititsmainenergyinsideahumanbodytokillcancercellsorinsidematerial.However,conventionalionacceleratorstendtobehugeinsizeandcost.Inthispaper,afutureintenselaserionacceleratorisdiscussedtomakethelaser-basedionacceleratorcompactandcontrollable.Theissuesinthelaserionacceleratorincludetheenergyefficiencyfromthelasertotheions,theionbeamcollimation,theionenergyspectrumcontrol,theionbeambunching,andtheionparticleenergycontrol.Inthestudy,eachcomponentisdesignedtocontroltheionbeamqualitybyparticlesimulations.Theenergyefficiencyfromthelasertoionsisimprovedbyusingasolidtargetwithafinesub-wavelengthstructureoranear-critical-densitygasplasma.Theionbeamcollimationisperformedbyholesbehindthesolidtargetoramulti-layeredsolidtarget.Thecontroloftheionenergyspectrumandtheionparticleenergy,andtheionbeambunchingaresuccessfullyrealizedbyamulti-stagelaser–targetinteraction.

简介：Inthepaper,relativisticfilamentationofintenselaserbeamininhomogeneousplasmaisinvestigatedbasedonthenonparaxialregiontheory.Theresultsshowthat,relativisticnonlinearityplaysamainroleinbeamfilamentation,andplasmainhomogeneityfurtherreinforcesthebeamfilamentation.Thecombinationeffectsofrelativisticnonlinearityandplasmainhomogeneitycangenerateparticularlyintenseandshortpulselaser.However,plasmainhomogeneityleadstoobviousfilamentationinstability.

简介：Ashortoverviewofthetheoryofaccelerationofthinfoilsdrivenbytheradiationpressureofsuperintenselasersispresented.Asimplecriterionforradiationpressuredominanceatintensitiesaround5×1020Wcm-2isgiven,andthepossibilityforfastenergygainintherelativisticregimeisdiscussed.

简介：TheexcitonicopticalabsorptionofGaAsbulksemiconductorsunderintenseterahertz(THz)radiationisinvesti-gatednumerically.Themethodofsolvinginitial-valueproblems,combinedwiththeperfectmatchedlayertechnique,isusedtocalculatetheopticalsusceptibility.InthepresenceofadrivingTHzfield,inadditiontotheusualexcitonpeaks,2preplicaofthedark2pexcitonandeven-THz-photon-sidebandsofthemainexcitonresonanceemergeinthecontinuumabovethebandedgeandbelowthemainexcitonresonance.Moreover,tounderstandtheshiftofthepositionofthemainexcitonpeakunderintenseTHzradiation,itisnecessarytotakeintoconsiderationboththedynamicalFranz-KeldysheffectandacStarkeffectsimultaneously.Formoderatefrequencyfields,themainexcitonpeakdecreasesandbroadensduetothefield-inducedionizationoftheexcitonswithTHzfieldincreasing.However,forhighfrequencyTHzfields,thecharacteristicsoftheexcitonrecurevenunderverystrongTHzfields,whichaccordswiththerecentexperimentalresultsqualitatively.

简介：OurexperimentsshowthatexternalfocusingandinitiallaserenergystronglyinfluencesfilamentgeneratedbythefemtosecondTi–sapphirelaserinair.Theexperimentalmeasurementsshowthefilamentlengthcanbeextendedbothbyincreasingthelaserenergyandfocallengthoffocusinglens.Ontheotherhand,theplasmafluorescenceemissioncanbeenhancedbyincreasingthelaserenergywithfixedfocallengthordecreasingthefocallength.Inaddition,thecollapsedistancemeasuredexperimentallyarelargerthanthecalculatedonesowingtothegroup-velocity-dispersioneffect.Inaddition,wefindthatthelinewidthsofthespectrallinesfromN2isindependentoffilamentpositions,laserenergiesandexternalfocusing.

简介：'Althoughvariousrisks,suchaspolicyrisk,demandchangingrisk,marketcompetitionrisk,pricefluctuationriskofrawmaterialandfinancialriskexisttovaryingdegrees,theinvestmentcrazeonthermalpowerprojectswouldnotcooldown,'anexpertwithChinaPowerEngineeringConsultingGroupCorporationsaid.

简介：Inourpreviouswork,aplasmaapproachforsingleattosecondpulse(AP)generationwasproposed.Afew-cyclerelativisticcircularlypolarizedlaserpulsewillinduceasingledrasticoscillationofplasmaboundary,fromwhichhigh-orderharmonicsandfurthermoreanultra-intensesingleAPcanbegeneratednaturallyafteritisreflected.Analyticalmodelandsimulationsbothdemonstratethattheprocessismostlyefficientasthepulsedurationisclosetotheplasmarespondingtime.Theeffectsofplasmadensityrampareanalyzedhere,suggestingthattheproposalisstillquiteefficientwithappropriatedensitygradientintheramp.Atlast,acombinedapproachisemployedtoobtainsingleAPwith30fsincidentlaser.Therelativelylarge-durationpulseisfirstlyshortenedbyadensitydroppingthinfoil,andthenreflectedfromanoverdenseplasmatarget.One-dimensionalsimulationshowsthata600assinglelightpulseisgeneratedwithpeakintensityof3×1020W/cm2.

简介：The45°scatteringofafemtosecond(60fs)intenselaserpulsewitha20nmFWHM(thefullwidthathalfmaximum)spectrumcenteredat790nmhasbeenstudiedexperimentallywhilefocusedinargonclustersatintensity～1016W/cra2.Scatteringspectraunderdifferentbackingpressuresandlaser-plasmainteractionlengthswereobtained,whichshowedspectralblueshifting,beamrefractionandcomplexmodulation.Theseionization-inducedeffectsrevealthemodulationoflaserpulsespropagatinginplasmasandtheexistingobstacleinlaserclusterinteractionathighlaserintensityandhighelectrondensity.

简介：Wepresentaninterferometrysetupandthedetailedfringeanalysismethodforintenseshortpulse(SP)laserexperiments.Theinterferometryschemewasrefinedthroughmultiplecampaignstoinvestigatetheeffectsofpre-plasmasonenergeticelectronsattheJupiterLaserFacilityatLawrenceLivermoreNationalLaboratory.Theinterferometerusedafrequencydoubled(λ=0.527μm)0.5pslongopticalprobebeamtomeasurethepre-plasmadensity,aninvaluableparametertobetterunderstandhowvaryingpre-plasmaconditionsaffectthecharacteristicsoftheenergeticelectrons.Thehardwareofthediagnostic,dataanalysisandexampledataarepresented.ThediagnosticsetupandtheanalysisprocedurecanbeemployedforanyotherSPlaserexperimentsandinterferograms,respectively.

简介：Strongfluorescenceemissionswereobservedfornitrogen,carbonmonoxide,andcarbondioxidemoleculesinintensefemtosecondlaserfields.Theseemissionscanbeassignedtothetransitionsofthemolecularionsfromtheexcitedelectronicstatestothegroundelectronicstates.Theformationmechanismswerediscussedandthelifetimesweremeasuredfortheseexcitedmolecularionsinintenselaserfields.

简介：Twocompactandintense2.45GHzpermanentprotonsourcesandtheircorrespondinglowenergybeamtransport(LEBT)systemsweredevelopedsuccessfullyforChinaAcceleratorDrivenSub-criticalsystem(C-ADS)in2014,oneofwhichwasbuiltatIMP,LanzhouandtheotheratIHEP,Beijing.Bothprotonsourcescandeliverstable10mA/35keVprotonbeamsatCWmodetotheentrancesofthedownstreamRFQs.AsshowninFig.1,thebeamsextractedbya3-electrodeextractionsystemaretransportedbytheLEBTsystem,whichiscomposedof2identicalsolenoids,andintothe3.2or2.1MeVradio-frequencyquadrupole(RFQ).Inordertoensuresuperconductingcavitiescommissioningandprotection,anelectrostatic-chopperhasbeendesignedandinstalledintheLEBTlinethatcanchopthecwbeamFig.2Totalhydrogenionbeamcurrentversusinputpower.intoapulsedone.Theachievedfall/risetimeofthechopperislessthan20ns.

简介：Atechniqueofelectronaccelerationinthecone-shapedstationarylaserfieldisproposed.Anelectronaccelerationinthislaserisstudied,whichshowsthatthereisnoelectronbunchingbutthereexistselectroncaptureinthislaserfield.

简介：

简介：Itisfoundthatthereisanupper-limitcriticalpowerforself-guidedpropagationofintenselasersinplasmainadditiontothewell-knownlower-limitcriticalpowersetbytherelativisticeffect.Abovethisupper-limitcriticalpower,thelaserpulseexperiencesdefocusingduetoexpulsionoflocalplasmaelectronsbythetransverseponderomotiveforce.Associatedwiththeupper-limitpower,alower-limitcriticalplasmadensityisalsofoundforagivenlaserspotsize,belowwhichself-focusingdoesnotoccurforanylaserpower.Boththeupper-limitpowerandthelower-limitdensityarederivedtheoreticallyandverifiedbytwo-dimensionalparticle-in-cellsimulations.Thepresentstudyprovidesnewguidanceforexperimentaldesigns,whereself-guidedpropagationoflasersisessential.

简介：

简介：在2004年7月的仲夏和在重降水的形成的冷空气的角色的严重降雨事件被使用中国和NCEP/NCAR分析的每天观察的降水数据调查。在西南中国的严重降雨是的结果表演仔细，与冷空气有关，从中间高度的纬度的活动，和事件发生在中间高度的纬度循环和低纬度的合作效果下面摘要的政体。它是合并一个冷旋涡在上与向北方登陆的台风和东方西南中国中间纬度旋涡，以及从进那分别地引起中间高度的大气的循环的三大改变在的正直的横过的马槽的突然的转变早、中间十天这个月。然后，长波浪的振幅很快放大，导致到在仲夏的低纬度的区域的冷空气的不平常的侵入。同时，温暖、潮湿的西南夏天季风是相当活跃的。在西南中国上的冷空气和夏天季风的强壮的相互作用在冷空气的南部的方面上导致大规模对流降雨。关于冷空气的活动，它能以三个突出的方法影响降雨。第一，上层的冷空气的进入被部分南方的上层的喷气经常伴随。相应第二等的发行量的上升分支，在喷气中心的左前面方面上，为降雨提供喜爱的动态向上的运动。第二，冷空气的向南方的运动贡献大气的baroclinic结构的建立，它将导致baroclinic骚乱。与冷空气的侵入联系的大气的骚乱能破坏潜在的不稳定性层化，释放对流可得到的势能(披肩)并且最后引起对流活动。另外，在与在底层的潮湿、温暖的空气的移流一起的上面的水平的干燥、冷的空气的移流过程为在降水区域的潜在的不稳定性的重建是相当重要的，它是贡献坚持的降雨的关键因素之一。

简介：Inthiswork,resultsonthestudyofthestructureandphotoluminescence(PL)propertiesofSiOxNythinfilmsarepresented.Thefilmsweredepositedatroomtemperatureusingadual-ion-beamco-sputteringsystem.TheXRDandTEMresultsshowthatthedepositedfilmshaveanamorphousstructure.IntheXPSresult,wefindN1sspectraconsistofonesymmetricsinglepeakat397.8eV,indicatingthatthenitrogenatomsaremainlybondedtosilicon.ItisinagreementtotheresultofFTIR.InSiOxNyfilms,anintensesinglePLpeakat590nmisobserved.Furthermore,withtheincreaseoftheNcontentintheSiOxNyfilms,theintensityofthePLpeakat590nmincreasesalot.ThePLpeakof590nmissuggestedtooriginatefromN-relateddefects.

简介：Wereportonatargetsystemsupportingautomatedpositioningofnano-targetswithaprecisionresolutionof4μminthreedimensions.Itreliesonaconfocaldistancesensorandamicroscope.Thesystemhasbeencommissionedtopositionnanometertargetswith1Hzrepetitionrate.Integratingourprototypeintothetable-topATLAS300TW-lasersystemattheLaboratoryforExtremePhotonicsinGarching,wedemonstratetheoperationofa0.5Hzlaser-drivenprotonsourcewithashot-to-shotvariationofthemaximumenergyabout27%foralevelofconfidenceof0.95.Thereasonoflasershootingexperimentsoperatedat0.5Hzratherthan1Hzisbecausethesynchronizationbetweenthenano-foiltargetpositioningsystemandthelasertriggerneedstoimprove.