Stability property of numerical Cherenkov radiation and its application to relativistic shock simulations

Publications of the Astronomical Society of Japan

Ikeya, Naoki¹  Matsumoto, Yosuke¹ 

[1] Department of Physics, Chiba University, 1-33 Yayoi, Inage-ku, Chiba, Chiba 263-8522, Japan

关键词: "acceleration of particles";    "cosmic rays";    plasmas;    "shock waves";   

DOI  :  10.1093/pasj/psv052

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

WestudiedthestabilitypropertyofnumericalCherenkovradiationinrelativisticplasmaflowsemployingparticle-in-cellsimulations.Usingtheimplicitfinite-differencetime-domainmethodtosolvetheMaxwellequations,wefoundthatnonphysicalinstabilitywasgreatlyinhibitedwithaCourant–Friedrichs–Lewy(CFL)numberof1.0.Thepresentresultcontrastswithrecentlyreportedresults(Vayet al.2011,J.Comp.Phys.,230,5908;Godfreyamp;Vay2013,J.Comp.Phys.,248,33;Xuet al.2013,Comput.Phys.Commun.,184,2503)inwhichmagicalCFLnumbersintherange0.5–0.7wereobtainedwithexplicitfieldsolvers.Inaddition,wefoundemployinghigher-ordershapefunctionsandanoptimalimplicitnessfactorfurthersuppressedlong-wavelengthmodesoftheinstability.Thefindingsallowedtheexaminationofthelong-termevolutionofarelativisticcollisionlessshockwithoutthegenerationofnonphysicalwaveexcitationsintheupstream.Thisachievementwillallowustoinvestigateparticleaccelerationsinrelativisticshocksassociatedwith,forexample,gamma-raybursts.

【 授权许可】

Unknown