4574

4302

كارشناسي ارشد

فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1387

دوازده، 79 ،[II] ص: مصور ، نمودار

ص.ع. به: فارسي وانگليسي

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88/4/31

كيوان آقابابايي ساماني

فيزيك

ID4302

به فارسي وانگليسي: قابل رويت در نسخه ديجيتال

Investigation of electron acoustic wave in laser plasma interactions Maryam Sharifi yasamin m@ph iut ac ir March 11 2009 Department of Physics Isfahan university of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor A Parvazian pavazin@cc iut ac irAbstractInteraction between electromagnetic waves and dense or over dense plasma has recently been noticed in manyaspects Damping of these waves could transfer energy Radio waves with appropriate wavelength stimulateelectrons in upper hybrid resonance and produce waves which are effective for heating of dense plasma in sphericaltokamaks Laser waves with wavelengths the range few hundreds nanometer have been used in over dense plasmas Phenomenon like scattering off of electron acoustic waves EAW with frequencies below the plasma frequency p which reflect incident waves produce instabilities in plasma that play important role for success of fusion A two dimensional 2D Vlasov Maxwell code was used to investigate the time evolution of the electrondistribution function in dense plasma Mega Amper Spherical tokamak and over dense plasma plasma at InertialConfinement Fusion We could calculate k D quantity by determining Debye length and using differentwavelengths It was found that because there were some instabilities as a result of stimulated electron scattering thiswave was observed at a frequency and phase velocity 0 54 p v 1 93vt e below that of the plasma frequency They could reduce the energy of driven laser besides trapping electrons and accelerating them In over denseplasma dispersion for electron acoustic wave was calculate for laser waves with wavelength the range few hundredsnanometer It was found that for maximum phase velocity v 3 6 vt e frequency of this acoustic wave was abovethat of the plasma frequency This wave can be used for heating the plasma In this research in addition to electron acoustic wave influence of polar magnetic field was investigated in MegaAmper Spherical Tokamak MAST In spite of the fact that external magnetic field at tokamas with small aspectratio like MAST do not have so much impression for heating the plasma the result of the simulation indicates thatpolar magnetic field plays important role for determining the total magnetic field and it can not be ignored Key WordsPlasma Electron acoustic wave Laser Vlasov code Magnetic field

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