The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep s...The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep space exploration.An experimental prototype,including diagnostic devices,was designed and constructed based on the principles of the RMF-FRC thruster,with an RMF frequency of 210 kHz and a maximum peak current of 2 kA.Under the rated operating conditions,the initial plasma density was measured to be 5×10^(17)m^(-3),and increased to 2.2×10^(19)m^(-3)after the action of RMF.The coupling efficiency of RMF was about 53%,and the plasma current reached 1.9 kA.The axial magnetic field changed in reverse by 155 Gauss,successfully reversing the bias magnetic field of 60 Gauss,which verifies the formation of FRC plasma.After optimization research,it was found that when the bias magnetic field is 100 Gauss,the axial magnetic field reverse variation caused by FRC is the highest at 164 Gauss.The experimental results are discussed and strategies are proposed to improve the performance of the prototype.展开更多
Conservation of parity plays a fundamental role in our understanding of various quantum processes.However,it is difficult to observe in atomic and molecular processes induced by a strong laser field due to their multi...Conservation of parity plays a fundamental role in our understanding of various quantum processes.However,it is difficult to observe in atomic and molecular processes induced by a strong laser field due to their multiphoton character and the large number of states involved.Here we report an effect of parity in strong-field Rydberg-state excitation(RSE)by comparing the RSE probabilities of the N_(2) molecule and its companion atom Ar,which has a similar ionization potential but opposite parity of its ground state.Experimentally,we observe an oscillatory structure as a function of intensity with a period of about 50 TW∕cm^(2) in the ratio between the RSE yields of the two species,which can be reproduced by simulations using the time-dependent Schrödinger equation(TDSE).We analyze a quantum-mechanical model,which allows for interference of electrons captured in different spatial regions of the Rydberg-state wave function.In the intensity-dependent RSE yield,it results in peaks with alternating heights with a spacing of 25 TW∕cm^(2) and at the same intensity for both species.However,due to the opposite parities of their ground states,pronounced RSE peaks in Ar correspond to less pronounced peaks in N_(2) and vice versa,which leads to the period of 50 TW∕cm^(2) in their ratio.Our work reveals a novel parity-related interference effect in the coherent-capture picture of the RSE process in intense laser fields.展开更多
基金supported by National Natural Science Foundation of China (NSFC) (Nos.62201217 and 51821005)。
文摘The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep space exploration.An experimental prototype,including diagnostic devices,was designed and constructed based on the principles of the RMF-FRC thruster,with an RMF frequency of 210 kHz and a maximum peak current of 2 kA.Under the rated operating conditions,the initial plasma density was measured to be 5×10^(17)m^(-3),and increased to 2.2×10^(19)m^(-3)after the action of RMF.The coupling efficiency of RMF was about 53%,and the plasma current reached 1.9 kA.The axial magnetic field changed in reverse by 155 Gauss,successfully reversing the bias magnetic field of 60 Gauss,which verifies the formation of FRC plasma.After optimization research,it was found that when the bias magnetic field is 100 Gauss,the axial magnetic field reverse variation caused by FRC is the highest at 164 Gauss.The experimental results are discussed and strategies are proposed to improve the performance of the prototype.
基金National Key Research and Development Program of China(2019YFA0307700)National Natural Science Foundation of China(12174148,12074144,12074239)+1 种基金Li Ka Shing Foundation STU-GTIIT Joint Research(2024LKSFG02)STU Scientific Research Initiation(NTF23036T).
文摘Conservation of parity plays a fundamental role in our understanding of various quantum processes.However,it is difficult to observe in atomic and molecular processes induced by a strong laser field due to their multiphoton character and the large number of states involved.Here we report an effect of parity in strong-field Rydberg-state excitation(RSE)by comparing the RSE probabilities of the N_(2) molecule and its companion atom Ar,which has a similar ionization potential but opposite parity of its ground state.Experimentally,we observe an oscillatory structure as a function of intensity with a period of about 50 TW∕cm^(2) in the ratio between the RSE yields of the two species,which can be reproduced by simulations using the time-dependent Schrödinger equation(TDSE).We analyze a quantum-mechanical model,which allows for interference of electrons captured in different spatial regions of the Rydberg-state wave function.In the intensity-dependent RSE yield,it results in peaks with alternating heights with a spacing of 25 TW∕cm^(2) and at the same intensity for both species.However,due to the opposite parities of their ground states,pronounced RSE peaks in Ar correspond to less pronounced peaks in N_(2) and vice versa,which leads to the period of 50 TW∕cm^(2) in their ratio.Our work reveals a novel parity-related interference effect in the coherent-capture picture of the RSE process in intense laser fields.
