Z-pinch experiments with two arrays consisting, respectively, of 32 4-μm- and 6-μm-diameter tungsten wires have been carried out on QiangGuang-1 facility with a current rising up to 1.5 MA in 80 ns. At early time of...Z-pinch experiments with two arrays consisting, respectively, of 32 4-μm- and 6-μm-diameter tungsten wires have been carried out on QiangGuang-1 facility with a current rising up to 1.5 MA in 80 ns. At early time of implosion, x-ray framing images show that the initial emission comes from the central part of arrays, and double clear emission rings, drifting to the anode and the cathode at 5×10^6 cm/s and 2.4×10^7 cm/s respectively, are often produced near the electrodes. Later, in a 4-μm-diameter tungsten wire array, filamentation caused by ohmic heating is prominent, and more than ten filaments have been observed. A radial inward shift of arrays starts at about 30 ns earlier than the occurrence of the x-ray peak power for both kinds of arrays, and the shrinkage rate of emission region is as high as 1.7×107 cm/s in a 4-μm-diameter tungsten wire array, which is two times higher than that in a 6-μm one. Emission from precursor plasmas is observed in implosion of 6-μm-diameter tungsten wire arrays, but not in implosion of a 4- μm-diameter tungsten wire array. Whereas, in a 4-μm-diameter tungsten wire array, the soft x-ray emission shows the growth of m=l instability in the plasma column, which is caused by current. The reasons for the discrepancy between implosions of 4-μm- and 6-μm-diameter tungsten wire arrays are explained.展开更多
Dense Z-pinch plasmas are powerful and energy-efficient laboratory sources of X-rays,and show the possibility to drive inertial confinement fusion(ICF).Recent advances in wire-array Z-pinch and Z-pinch dynamic hohlrau...Dense Z-pinch plasmas are powerful and energy-efficient laboratory sources of X-rays,and show the possibility to drive inertial confinement fusion(ICF).Recent advances in wire-array Z-pinch and Z-pinch dynamic hohlraum(ZPDH)researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper.Models are setup to study different physical processes.A full circuit model(FCM)was used to study the coupling between Z-pinch implosion and generator discharge.A mass injection model with azimuthal modulation was setup to simulate the wire-array plasma initiation,and the two-dimensional MHD code MARED was developed to investigate the Z-pinch implosion,MRT instability,stagnation and radiation.Implosions of nested and quasi-spherical wire arrays were also investigated theoretically and numerically.Key processes of ZPDH,such as the arrayefoam interaction,formation of the hohlraum radiation,as well as the following capsule ablation and implosion,were analyzed with different radiation magneto-hydrodynamics(RMHD)codes.An integrated 2D RMHD simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array plasma acceleration,shock generation and propagation,hohlraum formation,radiation ablation,and fuel compression.展开更多
Two curved crystal spectrometers are set up on the "QiangGuang-1" generator to measure the z-pinch plasma spectra emitted from planar aluminum wire array loads. Kodak Biomax-MS film and an IRD AXUVHS5# array are emp...Two curved crystal spectrometers are set up on the "QiangGuang-1" generator to measure the z-pinch plasma spectra emitted from planar aluminum wire array loads. Kodak Biomax-MS film and an IRD AXUVHS5# array are employed to record time-integrated and time-resolved free-bound radiation, respectively. The photon energy recorded by each detector is ascertained by using the L-shell lines of molybdenum plasma. Based on the exponential relation between the continuum power and photon energies, the aluminum plasma electron temperatures are measured. For the time-integrated diagnosis, several "bright spots" indicate electron temperatures between (450 eV- 520 eV) ± 35%. And for the time-resolved ones, the result shows that the electron temperature reaches about 800 eV±30% at peak power. The system satisfies the demand of z-pinch plasma electron temperature diagnosis on a - 1 MA facility.展开更多
Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The ...Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The backlighting images show clearly the processes similar to those occurring in the initial stages of a cylindrical wire-array Z-pinch, including the electric explosion of single wires characterised by the dense wire cores surrounded by a low-density coronal plasma, the expansion of the exploding wire, the sausage instability (m = 0) in the coronal plasma around each wire, the motion of the coronal plasma as well as the wire core toward the current centroid, the formation of the precursor plasma column with a twist structure something like that of higher mode instability, especially the kink instability (m = 1).展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 10035030).
文摘Z-pinch experiments with two arrays consisting, respectively, of 32 4-μm- and 6-μm-diameter tungsten wires have been carried out on QiangGuang-1 facility with a current rising up to 1.5 MA in 80 ns. At early time of implosion, x-ray framing images show that the initial emission comes from the central part of arrays, and double clear emission rings, drifting to the anode and the cathode at 5×10^6 cm/s and 2.4×10^7 cm/s respectively, are often produced near the electrodes. Later, in a 4-μm-diameter tungsten wire array, filamentation caused by ohmic heating is prominent, and more than ten filaments have been observed. A radial inward shift of arrays starts at about 30 ns earlier than the occurrence of the x-ray peak power for both kinds of arrays, and the shrinkage rate of emission region is as high as 1.7×107 cm/s in a 4-μm-diameter tungsten wire array, which is two times higher than that in a 6-μm one. Emission from precursor plasmas is observed in implosion of 6-μm-diameter tungsten wire arrays, but not in implosion of a 4- μm-diameter tungsten wire array. Whereas, in a 4-μm-diameter tungsten wire array, the soft x-ray emission shows the growth of m=l instability in the plasma column, which is caused by current. The reasons for the discrepancy between implosions of 4-μm- and 6-μm-diameter tungsten wire arrays are explained.
基金supported by the National Natural Science Fund of China(Nos.11405012,10975022,11275030,11105017,11135007,11471047,91330107)the Foundation of President of China Academy of Engineering Physics(No.2014-1-042)the Defense Industrial Technology Development Program(B1520133015).
文摘Dense Z-pinch plasmas are powerful and energy-efficient laboratory sources of X-rays,and show the possibility to drive inertial confinement fusion(ICF).Recent advances in wire-array Z-pinch and Z-pinch dynamic hohlraum(ZPDH)researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper.Models are setup to study different physical processes.A full circuit model(FCM)was used to study the coupling between Z-pinch implosion and generator discharge.A mass injection model with azimuthal modulation was setup to simulate the wire-array plasma initiation,and the two-dimensional MHD code MARED was developed to investigate the Z-pinch implosion,MRT instability,stagnation and radiation.Implosions of nested and quasi-spherical wire arrays were also investigated theoretically and numerically.Key processes of ZPDH,such as the arrayefoam interaction,formation of the hohlraum radiation,as well as the following capsule ablation and implosion,were analyzed with different radiation magneto-hydrodynamics(RMHD)codes.An integrated 2D RMHD simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array plasma acceleration,shock generation and propagation,hohlraum formation,radiation ablation,and fuel compression.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.10905047)
文摘Two curved crystal spectrometers are set up on the "QiangGuang-1" generator to measure the z-pinch plasma spectra emitted from planar aluminum wire array loads. Kodak Biomax-MS film and an IRD AXUVHS5# array are employed to record time-integrated and time-resolved free-bound radiation, respectively. The photon energy recorded by each detector is ascertained by using the L-shell lines of molybdenum plasma. Based on the exponential relation between the continuum power and photon energies, the aluminum plasma electron temperatures are measured. For the time-integrated diagnosis, several "bright spots" indicate electron temperatures between (450 eV- 520 eV) ± 35%. And for the time-resolved ones, the result shows that the electron temperature reaches about 800 eV±30% at peak power. The system satisfies the demand of z-pinch plasma electron temperature diagnosis on a - 1 MA facility.
基金supported by the National Natural Science Foundation of China (Grant No. 10635050)the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 200748)+2 种基金the International Atomic Energy Agency (Grant No. 14509)the Postdoctoral Science Foundation of China (Grant No. 20090450355)the Special Research Fund for the Doctoral Program of Higher Education,China (Grant No. 200800030037)
文摘Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The backlighting images show clearly the processes similar to those occurring in the initial stages of a cylindrical wire-array Z-pinch, including the electric explosion of single wires characterised by the dense wire cores surrounded by a low-density coronal plasma, the expansion of the exploding wire, the sausage instability (m = 0) in the coronal plasma around each wire, the motion of the coronal plasma as well as the wire core toward the current centroid, the formation of the precursor plasma column with a twist structure something like that of higher mode instability, especially the kink instability (m = 1).