Theory of the jitter radiation in a magnetized plasma accompanying a temperature gradient

Publications of the Astronomical Society of Japan

Hattori, Makoto¹  Fujiki, Kazushiro¹ 

[1] Astronomical Institute, Graduate school of science, Tohoku University, 6-3, Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan

关键词: instabilities;    plasmas;    "relativistic processes";   

DOI  :  10.1093/pasj/psw014

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Thelinearstabilityofamagnetizedplasmaaccompanyingatemperaturegradientisreexaminedbyusingplasmakinetictheory.Weproposethattheanisotropicvelocitydistributionfunctionshouldbedecomposedintotwocomponents.Oneisproportionaltothetemperaturegradientparalleltothebackgroundmagneticfield.Theotherisproportionaltothetemperaturegradientperpendiculartothebackgroundmagneticfield.Sincetheamplitudeoftheanisotropicvelocitydistributionfunctionisproportionaltotheheatconductivity,andtheheatconductivityperpendiculartothemagneticfieldisstronglyreduced,thefirstcomponentoftheanisotropicvelocitydistributionfunctionispredominant.Theanisotropicvelocitydistributionfunctioninducedbythetemperaturegradientalongthebackgroundmagneticfielddrivesplasmakineticinstabilityandcircularpolarizedmagneticplasmawavesareexcited.WeshowthattheinstabilityisalmostidenticaltotheWeibelinstabilityintheweaklymagnetizedplasma.However,inthecaseoftheinstabilitycausedbythetemperaturegradient,whetherwavevectorsofmodesareparalleltoorantiparalleltothebackgroundmagneticfield,thegrowthrateofonemodeissuppressedandthegrowthrateoftheothermodeisenhancedduetothebackgroundmagneticfield.Inthestronglymagnetizedplasma,onemodeisstabilizedandonlyoneofthemodesremainsunstable.Theformulaeforthejitterradiationspectrumemittedbyrelativisticelectronswhentheytravelthroughthemagnetizedplasmawiththeplasmawavesdrivenbytheinstabilityarededucedatthefirsttime.Weshowthatthesynchrotronemissionandthejitterradiationaresimultaneouslyemittedfromthesamerelativisticelectron.Thejitterradiationisexpectedtobecircularlypolarizedbutwithaverysmallpolarizationdegreesincealmostthesameamountsofleft-handedandright-handedcircularpolarizedmagneticwavesareexcitedbytheinstability.

【 授权许可】

Unknown