High quality ion beams are required by IMP cyclotron and atomic physics research, so it is important to research and measure beam emitt ance of ECR ion source. Intense beams extracted from ECR ion source usually have ...High quality ion beams are required by IMP cyclotron and atomic physics research, so it is important to research and measure beam emitt ance of ECR ion source. Intense beams extracted from ECR ion source usually have low energy, so it is suitable to use Electric-Sweep Scanner to measure the emittance. This kind of measurement is popularly used at ECR ion source, and it has some prominent merits such as high accuracy, very short time of data processing and easy expressing of the emittance pattern. So we designed and built this emittance scanner to measure emittance of the ion beams produced by LECR3 ion source. The structure of the ESS is shown in Fig.l, and the photo of the ESS is shown in Fig.2.展开更多
Magnetic confinement of fusion plasma has a wide range of issues to be addressed. Convective transport of plasma in the scrape-off layer of magnetic confinement devices is an interesting research topic for scientists ...Magnetic confinement of fusion plasma has a wide range of issues to be addressed. Convective transport of plasma in the scrape-off layer of magnetic confinement devices is an interesting research topic for scientists and engineers. The interest in scrape-off layer convective transport has grown in last two decades because of its effect on plasma interaction with the first wall and divertor. By increasing the particle flux into the far scrape-off layer, blobs negatively affect limiters, radio frequency antennas and the first wall. Increased convective heat transport influences core plasma confinement, at least in L-mode plasmas. Here we have reported blob formation in the absent of external magnetic field. It is observed that at low pressure -0.01 rob, transport seems to be dominated by diffusive process. At pressure 〉 1 mb, we observe convective transport in high speed imaging experiments. The role of background neutrals outside plasma boundary has the befitting answer for this phenomenon. Plasma temperature is the other key player. Another interesting observation is that at diffusive transport regime plasma life time is of the order of voltage pulse duration fed to plasma source, where as at convective transport regime plasma life time is increased appreciably.展开更多
The experimental set-up of SMBI system in HL-2A and the detail structure of the molecular beam valve with cooling trap are shown in Fig.l. The valve used for producing hydrogen cluster jet is a solenoid valve S99 with...The experimental set-up of SMBI system in HL-2A and the detail structure of the molecular beam valve with cooling trap are shown in Fig.l. The valve used for producing hydrogen cluster jet is a solenoid valve S99 with a nozzle orifice of 0.2 mm diameter. The distance between the nozzle of the valve and the edge plasma is about 1.28 m. A liquid nitrogen cryogenic trap is applied for cooling the valve body and decreasing the working gas temperature. The hydrogen cluster jet used for the experiments is in fact a free jet. For real gases, the adiabatic expansion of gas through a nozzle into vacuum results in substantial cooling in the frame of the moving gas. Atoms or molecules that interact weakly at low temperature can form clusters as a result. Attractive forces between atoms can be hydrogen bonding,展开更多
文摘High quality ion beams are required by IMP cyclotron and atomic physics research, so it is important to research and measure beam emitt ance of ECR ion source. Intense beams extracted from ECR ion source usually have low energy, so it is suitable to use Electric-Sweep Scanner to measure the emittance. This kind of measurement is popularly used at ECR ion source, and it has some prominent merits such as high accuracy, very short time of data processing and easy expressing of the emittance pattern. So we designed and built this emittance scanner to measure emittance of the ion beams produced by LECR3 ion source. The structure of the ESS is shown in Fig.l, and the photo of the ESS is shown in Fig.2.
文摘Magnetic confinement of fusion plasma has a wide range of issues to be addressed. Convective transport of plasma in the scrape-off layer of magnetic confinement devices is an interesting research topic for scientists and engineers. The interest in scrape-off layer convective transport has grown in last two decades because of its effect on plasma interaction with the first wall and divertor. By increasing the particle flux into the far scrape-off layer, blobs negatively affect limiters, radio frequency antennas and the first wall. Increased convective heat transport influences core plasma confinement, at least in L-mode plasmas. Here we have reported blob formation in the absent of external magnetic field. It is observed that at low pressure -0.01 rob, transport seems to be dominated by diffusive process. At pressure 〉 1 mb, we observe convective transport in high speed imaging experiments. The role of background neutrals outside plasma boundary has the befitting answer for this phenomenon. Plasma temperature is the other key player. Another interesting observation is that at diffusive transport regime plasma life time is of the order of voltage pulse duration fed to plasma source, where as at convective transport regime plasma life time is increased appreciably.
文摘The experimental set-up of SMBI system in HL-2A and the detail structure of the molecular beam valve with cooling trap are shown in Fig.l. The valve used for producing hydrogen cluster jet is a solenoid valve S99 with a nozzle orifice of 0.2 mm diameter. The distance between the nozzle of the valve and the edge plasma is about 1.28 m. A liquid nitrogen cryogenic trap is applied for cooling the valve body and decreasing the working gas temperature. The hydrogen cluster jet used for the experiments is in fact a free jet. For real gases, the adiabatic expansion of gas through a nozzle into vacuum results in substantial cooling in the frame of the moving gas. Atoms or molecules that interact weakly at low temperature can form clusters as a result. Attractive forces between atoms can be hydrogen bonding,
