On the experimental advanced superconducting tokamak(EAST), a pair of voltage and current probes(V/I probes) is installed on the ion cyclotron radio frequency transmission lines to measure the antenna input impedance,...On the experimental advanced superconducting tokamak(EAST), a pair of voltage and current probes(V/I probes) is installed on the ion cyclotron radio frequency transmission lines to measure the antenna input impedance, and supplement the conventional measurement technique based on voltage probe arrays. The coupling coefficients of V/I probes are sensitive to their sizes and installing locations, thus they should be determined properly to match the measurement range of data acquisition card. The V/I probes are tested in a testing platform at low power with various artificial loads. The testing results show that the deviation of coupling resistance is small for loads RL?>?2.5 Ω, while the resistance deviations appear large for loads RL?<?1.5 Ω, which implies that the power loss cannot be neglected at high VSWR. As the factors that give rise to the deviation of coupling resistance calculation, the phase measurement error is the more significant factor leads to deleterious results rather than the amplitude measurement error. To exclude the possible ingredients that may lead to phase measurement error, the phase detector can be calibrated in steady L-mode scenario and then use the calibrated data for calculation under H-mode cases in EAST experiments.展开更多
A new ICRF antenna has been designed in EAST, whose aims are to reduce the parallel RF electric fields Ell and to investigate the current drive using the fast magnetosonic wave. This antenna consists of four toroidall...A new ICRF antenna has been designed in EAST, whose aims are to reduce the parallel RF electric fields Ell and to investigate the current drive using the fast magnetosonic wave. This antenna consists of four toroidally spaced radiating straps. The electrical characteristics of the new antenna are estimated by using a three-dimensional electromagnetic commercial code. The S-parameters, RF current distribution and electromagnetic field distribution on and near the 4-strap antenna are analyzed, and the RF potentials influenced by antenna phasing and radial position are investigated.展开更多
The experimental advanced superconducting Tokamak has two suits of ion cyclotron radio frequency heating systems, in which the two antennas are of different structures. Their performance is assessed and compared by CS...The experimental advanced superconducting Tokamak has two suits of ion cyclotron radio frequency heating systems, in which the two antennas are of different structures. Their performance is assessed and compared by CST microwave studio. The radiating capacity of antennas and the arcing around them are estimated. The impurity release is analyzed by the radio frequency(RF) potential in the plasma sheath. The simulation results show that the radiating capacity for the folded antenna(I-port) is better than those for the double loops antenna(B-port). However,the folded antenna is worse than the double loops antenna in terms of breakdown. Moreover, the impurity production is relevant to spectrum shaping. The RF potential at(0, π,π, 0) phasing with the peak of spectrum k//= 8.5 m^(-1)is lower than the one with other phases. The impurity is reduced obviously when the folded antenna is powered with(0, π, π, 0) phasing.展开更多
Recent ion cyclotron resonance frequency（ICRF） coupling experiments for optimizing ICRF heating in high power discharge were performed on EAST. The coupling experiments were focus on antenna phasing and gas puffing,...Recent ion cyclotron resonance frequency（ICRF） coupling experiments for optimizing ICRF heating in high power discharge were performed on EAST. The coupling experiments were focus on antenna phasing and gas puffing, which were performed separately on two ports of the ion cyclotron resonance heating（ICRH） system of EAST. The antenna phasing was performed on the I-port antenna, which consists of four toroidally spaced radiating straps operating in multiple phasing cases; the coupling performance was better under low wave number ∣k;∣（ranging from 4.5 to 6.5）. By fuelling the plasma from gas injectors, placed as uniformly spaced array from top to bottom at each side limiter of the B-port antenna, which works in dipole phasing, the coupling resistance of the B-port antenna increased obviously.Furthermore, the coupling resistance of the I-port antenna was insensitive to a smaller rate of gas puffing but when the gas injection rate was more than a certain value(>1021 s;), a sharp increase in the coupling resistance of the I-port antenna occurred, which was mainly caused by the toroidal asymmetric boundary density arising from gas puffing. A more specific analysis is given in the paper.展开更多
基金National Natural Science Foundation of China under grant Nos. 11575237, 11775258, 11675213, 11375235 and 11375236National key research and development program (grant Nos. 2016YFA0400600 and 2016YFA0400601)+2 种基金International Scientific and Technological Cooperation Project of Anhui (grant No. 1704e1002207)the National Magnetic Confinement Fusion Science Programme of China (grant Nos. 2015GB101001 and 2013GB106001B)JSPSNRF-NSFC A3 Foresight Program in the field of Plasma Physics (NSFC No. 11261140328)
文摘On the experimental advanced superconducting tokamak(EAST), a pair of voltage and current probes(V/I probes) is installed on the ion cyclotron radio frequency transmission lines to measure the antenna input impedance, and supplement the conventional measurement technique based on voltage probe arrays. The coupling coefficients of V/I probes are sensitive to their sizes and installing locations, thus they should be determined properly to match the measurement range of data acquisition card. The V/I probes are tested in a testing platform at low power with various artificial loads. The testing results show that the deviation of coupling resistance is small for loads RL?>?2.5 Ω, while the resistance deviations appear large for loads RL?<?1.5 Ω, which implies that the power loss cannot be neglected at high VSWR. As the factors that give rise to the deviation of coupling resistance calculation, the phase measurement error is the more significant factor leads to deleterious results rather than the amplitude measurement error. To exclude the possible ingredients that may lead to phase measurement error, the phase detector can be calibrated in steady L-mode scenario and then use the calibrated data for calculation under H-mode cases in EAST experiments.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2015GB101001)National Natural Science Foundation of China(Nos.11375236 and 11375235)
文摘A new ICRF antenna has been designed in EAST, whose aims are to reduce the parallel RF electric fields Ell and to investigate the current drive using the fast magnetosonic wave. This antenna consists of four toroidally spaced radiating straps. The electrical characteristics of the new antenna are estimated by using a three-dimensional electromagnetic commercial code. The S-parameters, RF current distribution and electromagnetic field distribution on and near the 4-strap antenna are analyzed, and the RF potentials influenced by antenna phasing and radial position are investigated.
基金Supported by the National Magnetic Confinement Fusion Science Program of China(No.2015GB101001)the Natural Science Foundation of China(No.11375236)
文摘The experimental advanced superconducting Tokamak has two suits of ion cyclotron radio frequency heating systems, in which the two antennas are of different structures. Their performance is assessed and compared by CST microwave studio. The radiating capacity of antennas and the arcing around them are estimated. The impurity release is analyzed by the radio frequency(RF) potential in the plasma sheath. The simulation results show that the radiating capacity for the folded antenna(I-port) is better than those for the double loops antenna(B-port). However,the folded antenna is worse than the double loops antenna in terms of breakdown. Moreover, the impurity production is relevant to spectrum shaping. The RF potential at(0, π,π, 0) phasing with the peak of spectrum k//= 8.5 m^(-1)is lower than the one with other phases. The impurity is reduced obviously when the folded antenna is powered with(0, π, π, 0) phasing.
基金National key Research and Development program (Grant Nos. 2016YFA0400600 and 2016YFA0400601)National Magnetic Confinement Fusion Science Programme (Grant Nos. 2015GB101001 and 2013GB106001B)+1 种基金National Natural Science Foundation of China under Grant Nos. 11375235, 11675213 and 11375236JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics (NSFC no. 11261140328)
文摘Recent ion cyclotron resonance frequency（ICRF） coupling experiments for optimizing ICRF heating in high power discharge were performed on EAST. The coupling experiments were focus on antenna phasing and gas puffing, which were performed separately on two ports of the ion cyclotron resonance heating（ICRH） system of EAST. The antenna phasing was performed on the I-port antenna, which consists of four toroidally spaced radiating straps operating in multiple phasing cases; the coupling performance was better under low wave number ∣k;∣（ranging from 4.5 to 6.5）. By fuelling the plasma from gas injectors, placed as uniformly spaced array from top to bottom at each side limiter of the B-port antenna, which works in dipole phasing, the coupling resistance of the B-port antenna increased obviously.Furthermore, the coupling resistance of the I-port antenna was insensitive to a smaller rate of gas puffing but when the gas injection rate was more than a certain value(>1021 s;), a sharp increase in the coupling resistance of the I-port antenna occurred, which was mainly caused by the toroidal asymmetric boundary density arising from gas puffing. A more specific analysis is given in the paper.
