主持人：刘文副研究员
时间：2025年5月26日（周一）10:00
地点：犀浦校区二教2539会议室
腾讯会议：643-376-296
题目：Particle-In-CellSimulationonAstrophysicalPlasmas
主讲人：王振宇副研究员
中国科学院磁约束核聚变物理前沿全国重点实验室副研究员
2016年博士毕业于美国奥本大学，2016年9月起在普林斯顿大学做博士后，2019年起在普林斯顿大学等离子体物理实验室任AssociateResearchPhysicist。研究兴趣主要为计算等离子体物理，特别是粒子模拟算法及代码的开发，及其在天体和聚变等离子体中的应用。在美期间作为子课题负责人参与美国能源部基于先进计算的科学发现计划项目(SciDACHigh-fidelityBoundaryPlasmaSimulation)，作为项目骨干参与美国能源部百亿亿级超算应用开发计划(ExascaleComputingProject-WholeDeviceModeling)，作为PI主持的研究受到美国能源部面上项目资助（DE-SC0017908）。近期由中国科学院引进回国。
Abstract:Particle-In-Cell(PIC)simulationisapowerfultooltostudyplasmakinetics.Inthistalk,IwillshowapplyingPICmethodontheproblemsofastrophysicalplasmas.Firstly,IpresentthemodelingandinterpretationoflaserexperimentsdesignedtogeneratehighMachnumbermagnetizedcollisionlessshocksonOMEGA-EPfacility.Intheexperiment,alaser-producedhighvelocityplasmacollideswithamagnetized,pre-ablatedplasma.Protonradiographyshowsamovingregionofprotondeficitfollowedbyasharpenhancementofprotondensity.Thesefeaturesareproducedbygradientsinpropagatingcompressedmagneticfield.Ourteamcomparethedatatotheresultsof3DPICsimulations,explaintheobliquemovingfeaturesintroducedbydensitygradientsinexpandingplasmaandbycurvatureoftheimposedmagneticfield,andidentifythenarrowingofprotondeficitregionwidthwithasignatureofstrongmagneticovershoot.Wedeterminetheboundaryofpre-ablatedbackgroundplasmabycomparingwithradiographyoflasershotswithonlybackgroundplasmapresent.Wemeasurethestrengthofmagneto-inertialfusionelectricaldischargesystem(MIFEDS)fieldbymagneticdeflection.WeconcludethatourexperimentshavereproduciblyachievedmagnetizedshockswithAlfvenicMachnumber3to9inlaboratoryconditions.Secondly,weinvestigated3-DlinearinstabilitiesofHarriscurrentsheetunderarealisticion-to-electronmassratioandafiniteguidefield.Theexcitationand3-Dpropertiesoflowerhybriddriftinstability(LHDI)aredemonstrated.WestudythepropertiesofcurrentsheetinstabilitiesbyemployingGyrokineticelectronandFullykineticion(GeFi)particlesimulationcode.ItisfoundthatpartoftheenergyoftheLHDImodespenetratestothecurrentsheetcenterinthenonlinearstage.Thesaturationlevelofmagneticfieldatthecurrentsheetcenterisanorderofmagnitudesmallerthanthatatthecurrentsheetedge.TheGeFisimulationresultsarecomparedwiththefullykineticPICsimulations.
