A magnetic field produced by a current flowing through the plasma grid(PG) is one of the solutions to reduce the collisional loss of negative ions in a negative ion source, which reduces the electron temperature in fr...A magnetic field produced by a current flowing through the plasma grid(PG) is one of the solutions to reduce the collisional loss of negative ions in a negative ion source, which reduces the electron temperature in front of the PG. However, the magnetic field diffused into the driver has some influence on the plasma outflowing. In order to investigate the effect of changing this magnetic field on the outflowing of plasma from the driver, a circular ring(absorber) of high permeability iron has been introduced at the driver exit, which can reduce the magnetic field around it and improve plasma outflowing. With the application of the absorber, the electron density is increased by about 35%, and the extraction current measured from the extraction grid is increased from 1.02 A to 1.29 A. The results of the extraction experiment with cesium injection show that both the extraction grid(EG) current and H-current are increased when the absorber is introduced.展开更多
Since the high efficiency discharge is critical to the radio-frequency ion thruster(RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy...Since the high efficiency discharge is critical to the radio-frequency ion thruster(RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy correction of the electron energy distribution function(EEDF) are applied to the analysis of the RIT discharge. In the meantime, the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region. The beam current simulation results, with the hybrid model, agree well with the experimental results, and the error is lower than 11%, which shows the validity of the model. The further study shows there is an optimal ratio for the radio-frequency(RF) power and the beam current extraction power under the fixed RIT configuration. And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold(about 87 W). As the input parameters of the hybrid model are all the design values, it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.展开更多
An inductively coupled radio frequency ion source has been developed and its extraction characteristics measured. Beam current density up to 0.11 mA/ cm2 was obtained with argon at a rf discharge power of about 140 W....An inductively coupled radio frequency ion source has been developed and its extraction characteristics measured. Beam current density up to 0.11 mA/ cm2 was obtained with argon at a rf discharge power of about 140 W. The dependences of ion beam on the discharge parameters such as rf source power, gas pressure and gas flow rate was studied.展开更多
Various ion sources are key components to prepare functional coatings,such as diamond-like carbon(DLC)films.In this article,we present our trying of surface modification on basis of Si-incorporation diamond-like carbo...Various ion sources are key components to prepare functional coatings,such as diamond-like carbon(DLC)films.In this article,we present our trying of surface modification on basis of Si-incorporation diamond-like carbon(Si-DLC)produced by a magnetic field enhanced radio frequency ion source,which is established to get high density plasma with the help of magnetic field.Under proper deposition process,a contact angle of 111°hydrophobic surface was achieved without any surface patterning,where nanostructure SiC grains appeared within the amorphous microstructure.The surface property was influenced by ion flow parameters as well as the resultant surface microstructure.The magnetic field enhanced radio frequency ion source developed in this paper was useful for protective film applications.展开更多
Huazhong University of Science and Technology has developed an experimental setup of a radio frequency(RF) driven negative hydrogen ion source,to investigate the physics of production and extraction of the H^(-)ions f...Huazhong University of Science and Technology has developed an experimental setup of a radio frequency(RF) driven negative hydrogen ion source,to investigate the physics of production and extraction of the H^(-)ions for neutral beam injection in nuclear fusion reactors.The main design parameters of the ion source are:RF power ≤40 kW;extraction voltage ≤10kV;accelerator voltage ≤20 kV.This paper gives an overview of the progress of the ion source with particular emphasis on some issues.The RF driver and source plasma are analyzed and optimized in terms of impedance matching,plasma characteristics and power coupling.In regard to the simulation analysis,a plasma model based on the particle-in-cell method and a beam trajectory model considering beam stripping loss are developed to investigate the plasma and negative ions transport inside the ion source.Furthermore,a collisional radiative model of H and H2is built for plasma optical diagnosis.展开更多
基金supported by the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)National Natural Science Foundation of China(No.11975264)。
文摘A magnetic field produced by a current flowing through the plasma grid(PG) is one of the solutions to reduce the collisional loss of negative ions in a negative ion source, which reduces the electron temperature in front of the PG. However, the magnetic field diffused into the driver has some influence on the plasma outflowing. In order to investigate the effect of changing this magnetic field on the outflowing of plasma from the driver, a circular ring(absorber) of high permeability iron has been introduced at the driver exit, which can reduce the magnetic field around it and improve plasma outflowing. With the application of the absorber, the electron density is increased by about 35%, and the extraction current measured from the extraction grid is increased from 1.02 A to 1.29 A. The results of the extraction experiment with cesium injection show that both the extraction grid(EG) current and H-current are increased when the absorber is introduced.
基金supported by National Natural Science Foundation of China under Grant No. 11702123
文摘Since the high efficiency discharge is critical to the radio-frequency ion thruster(RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy correction of the electron energy distribution function(EEDF) are applied to the analysis of the RIT discharge. In the meantime, the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region. The beam current simulation results, with the hybrid model, agree well with the experimental results, and the error is lower than 11%, which shows the validity of the model. The further study shows there is an optimal ratio for the radio-frequency(RF) power and the beam current extraction power under the fixed RIT configuration. And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold(about 87 W). As the input parameters of the hybrid model are all the design values, it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.
基金This work was supported by National Natural Foundation of China No.19835030.
文摘An inductively coupled radio frequency ion source has been developed and its extraction characteristics measured. Beam current density up to 0.11 mA/ cm2 was obtained with argon at a rf discharge power of about 140 W. The dependences of ion beam on the discharge parameters such as rf source power, gas pressure and gas flow rate was studied.
文摘Various ion sources are key components to prepare functional coatings,such as diamond-like carbon(DLC)films.In this article,we present our trying of surface modification on basis of Si-incorporation diamond-like carbon(Si-DLC)produced by a magnetic field enhanced radio frequency ion source,which is established to get high density plasma with the help of magnetic field.Under proper deposition process,a contact angle of 111°hydrophobic surface was achieved without any surface patterning,where nanostructure SiC grains appeared within the amorphous microstructure.The surface property was influenced by ion flow parameters as well as the resultant surface microstructure.The magnetic field enhanced radio frequency ion source developed in this paper was useful for protective film applications.
基金supported by the National Key R&D Program of China(No.2017YFE0300105)National Natural Science Foundation of China(Nos.11775088 and 12005074)the Fundamental Research Funds for the Central Universities,HUST(No.2021XXJS013)
文摘Huazhong University of Science and Technology has developed an experimental setup of a radio frequency(RF) driven negative hydrogen ion source,to investigate the physics of production and extraction of the H^(-)ions for neutral beam injection in nuclear fusion reactors.The main design parameters of the ion source are:RF power ≤40 kW;extraction voltage ≤10kV;accelerator voltage ≤20 kV.This paper gives an overview of the progress of the ion source with particular emphasis on some issues.The RF driver and source plasma are analyzed and optimized in terms of impedance matching,plasma characteristics and power coupling.In regard to the simulation analysis,a plasma model based on the particle-in-cell method and a beam trajectory model considering beam stripping loss are developed to investigate the plasma and negative ions transport inside the ion source.Furthermore,a collisional radiative model of H and H2is built for plasma optical diagnosis.
