The Theory Research For The Effects Of ICRH Antenna Current And Plasma Density Distribution On Plasma Heating

Ion cyclotron Range of Frequency(ICRF) heating has been verified to be one ofthe main auxiliary heating methods in Tokamaks by many experiments and theory.But with increasing of Tokamak devices, the demand for the power of ICRF wavewhich is coupled with plasma is increasing. So the optimization scheme of how toimprove the antenna coupling power is still the focus of the research in this field andcutting edge. Because of the parameters such as the antenna structure, the spacebetween antenna and plasma, plasma distribution has an important influence onelectromagnetic wave excitation and spread. In order to reduce radio-frequency wavesenergy losses as much as possible and make the ion cyclotron heating antennacoupling efficiency be higher, it is necessary for us to deeply study on the mechanismof ion cyclotron resonance heating.The coupling of Ion cyclotron wave with plasma is numerically stimulated byusing a plasma slab model and a three-dimensional antenna model. The Maxwellequations in the vacuum and the fast magnetosonic wave equations in the plasma areresolved respectively by Green’s function method and a variable step lengthfourth-order Runge-Kutta method, on the condition that fast magnetosonic waves areabsorbed completely in the plasma and electromagnetic characters of the plasma aredescribed with the dielectric tensor of “cool” plasma.Variation of antenna couplingpower versus the central region of plasma density, parabolic fringe density,thescrape-off layer edge density, the poloidal phase difference or the toroidal phasedifference are calculated. The simulation results show that under certain experimentalconditions,Ion cyclotron wave is better coupled with plasma by increasing the centralregion of plasma density or the scrape-off layer density,as well as decreasing densitygradient of the parabolic region or the exponential fall-off region,and when thetoroidal phase difference equals to π, the ion cyclotron resonance heating effect is best.