رانش جريان و ديفيوژن ذرات با استفاده از معادله فاكر-پلانك درتو كامك هاي DIII-D JET، MAST، NSTX

چكيده انگليسي :

Current drive and plasma particles diffusion by Fokker Planck equation in NSTX MAST JET and DIII D tokamaks Ali Asghar Molavi Chobini aliasghar molavi64@yahoo com September 2010 Department of Physics Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Farsi Dr Akbar Parvazian mail parvazin@cc iut ac irAbstractOperation of tokamak fusion energy reactors requires non inductive current generation in the plasma forconfinement A variety of methods have been proposed to provide continuous current including methods thatutilize particle beams or radio frequency waves in any of several frequency regimes One important method forfusion plasma heating is the using of radio waves In recent years there has been considerable interest ingenerating steady state currents in plasma with RF waves In particular it was predicted that these currentscould be efficiently generated by waves having phase velocities several times the electron thermal speed Thisprediction has been confirmed by numerous experiments in which the current was driven by lower hybridwaves These results allow us to contemplate a steady state tokamak reactor in which the toroidal current isdriven by lower hybrid waves From a theoretical point of view the main component in these experiments is thedc electric field which opposes the increase of the plasma current The electric field is also present in schemeswhere the RF is used to recharge the transform at constant current This theory was also predicted that RFenergy could be efficiently converted to poloidal field energy if the wave phase velocity were approximatelyequal to the electron runaway velocity Poloidal field compresses the plasma and the plasma edge heatsdissipation and it will prevent possible further treatment that leads to fusion for us The interaction of radio frequency waves with plasma is described by a Fokker Planck equation with an added quasi linear term thatpresence of such sentence can be searched in particle collisions To solve this equation take the plasma then tobe azimuthally symmetric about the magnetic field and homogeneous the Fokker Planck equation then reducesto an equation in time and two velocity dimensions This simplified model yields a wealth of interesting physicsand furthermore illustrates the main numerical problems encountered in more complicated situations In additionto the collision term the equation will include the effects of externally injected RF power via a quasi lineardiffusion term and a dc electric field We have used LSC code for computation of the Fokker Planck equationand simulation of lower hybrid waves injected The Lower hybrid Simulation Code LSC is a computationalmodel of lower hybrid current drive in the presence of an electric field Details of geometry plasma profiles andcircuit equations are treated Two dimensional velocity space effects are approximated in a one dimensionalFokker Planck treatment In this project simulation of injected lower hybrid waves for NSTX MAST JET andDIII D tokamaks have been performed The results of this project show that spherical torus have betterperformance than torque tokamaks This condition causes the fusion reaction self sustaining realized should bebetter and the possibility of nuclear fusion power and performance is provided Key WordsLower hybrid waves LH Fokker Planck equation diffusion quasi linear LSC code NSTX MAST JET andDIII D tokamaks

مولوي چوبيني، علي اصغر

رانش جريان و ديفيوژن ذرات با استفاده از معادله فاكر-پلانك درتو كامك هاي DIII-D JET، MAST، NSTX

موج دوگانه ي پايين ﴿LH﴾ , برنامه محاسباتي Lsc