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
A review of X-pinches of various configurations and of different materials as an X-ray source for various applications is presented. Theadvantages and disadvantages of different designs of X-pinches as a load for gene...A review of X-pinches of various configurations and of different materials as an X-ray source for various applications is presented. Theadvantages and disadvantages of different designs of X-pinches as a load for generators with a wide range of output parameters and as a sourceof X-ray radiation for X-ray point-projection imaging were analyzed.展开更多
The current and the voltage of an X-pinch were measured. The inductance of the X-pinch was assumed to be a constant and estimated by the calculation of the magnetic field based on the well-known Biot–Savart’s Law. T...The current and the voltage of an X-pinch were measured. The inductance of the X-pinch was assumed to be a constant and estimated by the calculation of the magnetic field based on the well-known Biot–Savart’s Law. The voltage of the inductance was calculated with L · di/dt and subtracted from the measured voltage of the X-pinch. Then, the resistance of the X-pinch was determined and the following results were obtained. At the start of the current flow the resistance of the exploding wires is several tens of Ohms, one order of magnitude, higher than the metallic resistance of the wires at room temperature, and then it falls quickly to about 1 , which reflects the physical processes occurring in the electrically exploding wires, i.e., a current transition from the highly resistive wire core to the highly conductive plasma. It was shown that the inductive contribution to the voltage of the X-pinch is less than the resistive contribution. For the wires we used, the wires’ material and diameter have no strong influence on the resistance of the X-pinch, which may be explained by the fact that the current flows through the plasma rather than through the metallic wire itself. As a result, the current is almost equally divided between two parallel X-pinches even though the diameter and material of the wires used for these two X-pinches are significantly different.展开更多
Two methods of using the X-pinch as a source of X-ray radiation for radiography of biological objects are presented. X-pinches are found to be a very flexible method for generation of radiation over a wide spectral ra...Two methods of using the X-pinch as a source of X-ray radiation for radiography of biological objects are presented. X-pinches are found to be a very flexible method for generation of radiation over a wide spectral range and provide a high spatial and temporal resolution.展开更多
利用PPG-1脉冲电流源(400 k A,100 ns),同时驱动X-pinch和双丝Z箍缩负载.用X-pinch作为X射线源,对双丝Z箍缩进行了轴向背光照相的初步实验.得到了双丝Z箍缩在r-θ平面上随时间演化的图像,观察到了丝阵Z箍缩所有早期过程,包括丝芯膨胀、...利用PPG-1脉冲电流源(400 k A,100 ns),同时驱动X-pinch和双丝Z箍缩负载.用X-pinch作为X射线源,对双丝Z箍缩进行了轴向背光照相的初步实验.得到了双丝Z箍缩在r-θ平面上随时间演化的图像,观察到了丝阵Z箍缩所有早期过程,包括丝芯膨胀、冕层等离子体产生、等离子体向丝阵中心的运动、先驱等离子体形成.利用阶跃光楔滤片,对上述背光图像进行了等离子体质量面密度的标定,首次得到了在r-θ平面上双丝Z箍缩等离子体质量面密度的时空分布图像.展开更多
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）.
基金The experiments carried out on the Nene,XP and COBRA generators were partly supported by the Stewardship Sciences Academic Alliances Program of the NNSA under DOE Cooperative Agreement No.DE-NA-0001836The experiments carried out on the BIN,MINI and KING generators were partly supported by the Russian Foundation for Basic Research,projects Nos.17-02-0039,18-08-00631an agreement with Cornell University,under Prime Agreement DE-NA0003764 from DOE.
文摘A review of X-pinches of various configurations and of different materials as an X-ray source for various applications is presented. Theadvantages and disadvantages of different designs of X-pinches as a load for generators with a wide range of output parameters and as a sourceof X-ray radiation for X-ray point-projection imaging were analyzed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 51177086, 11135007, and 51237006)the Special Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200800030037)the Research Fund of the State Key Laboratory of Power System (Grant No. SKLD09M05)
文摘The current and the voltage of an X-pinch were measured. The inductance of the X-pinch was assumed to be a constant and estimated by the calculation of the magnetic field based on the well-known Biot–Savart’s Law. The voltage of the inductance was calculated with L · di/dt and subtracted from the measured voltage of the X-pinch. Then, the resistance of the X-pinch was determined and the following results were obtained. At the start of the current flow the resistance of the exploding wires is several tens of Ohms, one order of magnitude, higher than the metallic resistance of the wires at room temperature, and then it falls quickly to about 1 , which reflects the physical processes occurring in the electrically exploding wires, i.e., a current transition from the highly resistive wire core to the highly conductive plasma. It was shown that the inductive contribution to the voltage of the X-pinch is less than the resistive contribution. For the wires we used, the wires’ material and diameter have no strong influence on the resistance of the X-pinch, which may be explained by the fact that the current flows through the plasma rather than through the metallic wire itself. As a result, the current is almost equally divided between two parallel X-pinches even though the diameter and material of the wires used for these two X-pinches are significantly different.
文摘Two methods of using the X-pinch as a source of X-ray radiation for radiography of biological objects are presented. X-pinches are found to be a very flexible method for generation of radiation over a wide spectral range and provide a high spatial and temporal resolution.
文摘利用PPG-1脉冲电流源(400 k A,100 ns),同时驱动X-pinch和双丝Z箍缩负载.用X-pinch作为X射线源,对双丝Z箍缩进行了轴向背光照相的初步实验.得到了双丝Z箍缩在r-θ平面上随时间演化的图像,观察到了丝阵Z箍缩所有早期过程,包括丝芯膨胀、冕层等离子体产生、等离子体向丝阵中心的运动、先驱等离子体形成.利用阶跃光楔滤片,对上述背光图像进行了等离子体质量面密度的标定,首次得到了在r-θ平面上双丝Z箍缩等离子体质量面密度的时空分布图像.
