We numerically simulate the temporal evolutions of the densities of charged and neutral species in a plasma generated with repetitively pulsed discharge in atmospheric environment at 60 km altitude. The particles are ...We numerically simulate the temporal evolutions of the densities of charged and neutral species in a plasma generated with repetitively pulsed discharge in atmospheric environment at 60 km altitude. The particles are divided into three categories according to their temporal behaviour. All charged particles exhibit oscillations with the same frequency as the driven power. Densities of elements O, N and H increase in a long-time scale. Densities of O3 and NO increase firstly and then decrease at t=0.65s; in particular, they have very similar density evolution profiles to each other.展开更多
A program is developed to calculate the ion energy distributions （IEDs） of Ar2^＋ making use of a simplified kinetic model with a combination of Monte Carlo method. Several coefficients are used to realize good matc...A program is developed to calculate the ion energy distributions （IEDs） of Ar2^＋ making use of a simplified kinetic model with a combination of Monte Carlo method. Several coefficients are used to realize good match between the calculated and measured results. Some important assumptions are confirmed： argon excimer ions have short lifetime, hence they are formed in a short range before the collecting electrode. The excimer ions that encounter collisions will be discarded because they turn to other ion species after they collide with argon atoms. From the calculated results some plasma parameters such as the cross section or neutral density in discharge could be evaluated.展开更多
Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to th...Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbax is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.展开更多
A helicon mode discharge is realized in a newly erected set-up and two jumps are observed in the variation of plasma density with the controlled magnetic field,which is a typical characteristic of helicon mode dischar...A helicon mode discharge is realized in a newly erected set-up and two jumps are observed in the variation of plasma density with the controlled magnetic field,which is a typical characteristic of helicon mode discharge.A reasonable explanation is proposed for the appearance of the density jumps.The helicon wavelength is evaluated to be about 20 cm and it is nearly constant in the helicon mode discharge.The density obtained is nearly up to 3.5 × 10^(18)m^(-3) with only 0.5Pa argon pressure and 300W radio frequency power supply,and it is more than one magnitude higher than that in other discharges at comparable pressures and input powers.The electron temperature is found to be increased as the pressure is decreased.展开更多
文摘We numerically simulate the temporal evolutions of the densities of charged and neutral species in a plasma generated with repetitively pulsed discharge in atmospheric environment at 60 km altitude. The particles are divided into three categories according to their temporal behaviour. All charged particles exhibit oscillations with the same frequency as the driven power. Densities of elements O, N and H increase in a long-time scale. Densities of O3 and NO increase firstly and then decrease at t=0.65s; in particular, they have very similar density evolution profiles to each other.
文摘A program is developed to calculate the ion energy distributions （IEDs） of Ar2^＋ making use of a simplified kinetic model with a combination of Monte Carlo method. Several coefficients are used to realize good match between the calculated and measured results. Some important assumptions are confirmed： argon excimer ions have short lifetime, hence they are formed in a short range before the collecting electrode. The excimer ions that encounter collisions will be discarded because they turn to other ion species after they collide with argon atoms. From the calculated results some plasma parameters such as the cross section or neutral density in discharge could be evaluated.
基金supported by International Cooperation Project of Ministry of Science and Technology of China(4.1.P2.CN.01/1A)
文摘Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbax is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.
文摘A helicon mode discharge is realized in a newly erected set-up and two jumps are observed in the variation of plasma density with the controlled magnetic field,which is a typical characteristic of helicon mode discharge.A reasonable explanation is proposed for the appearance of the density jumps.The helicon wavelength is evaluated to be about 20 cm and it is nearly constant in the helicon mode discharge.The density obtained is nearly up to 3.5 × 10^(18)m^(-3) with only 0.5Pa argon pressure and 300W radio frequency power supply,and it is more than one magnitude higher than that in other discharges at comparable pressures and input powers.The electron temperature is found to be increased as the pressure is decreased.
