An experiment on 100 k J laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums.These hohlraums are designed to posses...An experiment on 100 k J laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums.These hohlraums are designed to possess one open end and one laser entrance hole(LEH)with different diameters,which would or not result in the blocking of the LEH.An x-ray streak camera that is set at 16 degrees with respect to the hohlraum axis is applied to acquire the timeresolved x-ray images from the open end.Based on the images,we can study the evolutions of the wall plasma,corona bubble plasma and LEH plasma simultaneously through an equivalent view field of hohlraum interior.Multi-group flat response x-ray detectors are applied to measure the x-ray fluxes.In order to understand these characteristics,our two-dimensional radiation hydrodynamic code is used to simulate the experimental results.For the accuracy of reproduction,dielectronic recombination and two parameter corrections are applied in our code.Based on the comparison between experiments and simulations,we quantitatively understand the blocking process of LEH and the motion effects of other plasmas.The calibrated code is beneficial to design the gas-filled hohlraum in a nearby parameter space,especially the limit size of LEH.展开更多
In this paper,we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study.From our theoretical study,the octahedral spherical hohlraums with 6 Laser Entrance Holes(LEHs)of octa...In this paper,we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study.From our theoretical study,the octahedral spherical hohlraums with 6 Laser Entrance Holes(LEHs)of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7.In addition,the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology.We studied the laser arrangement and constraints of the octahedral spherical hohlraums,and gave a design on the laser arrangement for ignition octahedral hohlraums.As a result,the injection angle of laser beams of 50°-60°was proposed as the optimum candidate range for the octahedral spherical hohlraums.We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields,in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport.We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums,the rugby hohlraums and the cylindrical hohlraums,and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive.Up till to now,we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG)laser facilities,including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums,spherical hohlraum energetics on the SGIII prototype laser facility,and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.展开更多
The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all ...The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all weather surface link between the two districts of Ladakh region (Kargil and Leh). The area under investigation experiences high vehicular traffic, particularly between March and August, as in the remaining months the Kargil and Leh districts?remain cutoff?from each other due to bad weather. In recent years, frequent occurrences of slope failures along the highway primarily affect the smooth functioning of the traffic movement which severely affects the life of the people of the area. Strategically, this road network is very important and plays a significant role in transportation and other activities. In order to ensure the stability of road network in the area, it becomes extremely important to understand the triggering mechanism of these failures. The present study made an attempt in this direction and the Slope Mass Rating (SMR) method has been used for slope stability analysis at different locations. The stability of the slopes was also assessed using kinematic analysis conjointly with SMR to identify the types of failure and its potential failure directions associated with each slope. The result obtained after calculating RMR from the selected facets ranges from 11 to 89 with lower values indicating presence of potentially unstable areas. Results have shown that in a total of 20 facets, 65.28% belong to wedge failure, 22.26%?belong to toppling failure and 12.45% belong to plane failure.展开更多
基金supported by National Natural Science Foundation of China(Nos.12075219,12105269 and 12175210)。
文摘An experiment on 100 k J laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums.These hohlraums are designed to possess one open end and one laser entrance hole(LEH)with different diameters,which would or not result in the blocking of the LEH.An x-ray streak camera that is set at 16 degrees with respect to the hohlraum axis is applied to acquire the timeresolved x-ray images from the open end.Based on the images,we can study the evolutions of the wall plasma,corona bubble plasma and LEH plasma simultaneously through an equivalent view field of hohlraum interior.Multi-group flat response x-ray detectors are applied to measure the x-ray fluxes.In order to understand these characteristics,our two-dimensional radiation hydrodynamic code is used to simulate the experimental results.For the accuracy of reproduction,dielectronic recombination and two parameter corrections are applied in our code.Based on the comparison between experiments and simulations,we quantitatively understand the blocking process of LEH and the motion effects of other plasmas.The calibrated code is beneficial to design the gas-filled hohlraum in a nearby parameter space,especially the limit size of LEH.
基金supported by the National Fundamental Research Program of China(Contact No.11475033 and 11405011)CAEP(Contact No.2013A0102002).
文摘In this paper,we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study.From our theoretical study,the octahedral spherical hohlraums with 6 Laser Entrance Holes(LEHs)of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7.In addition,the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology.We studied the laser arrangement and constraints of the octahedral spherical hohlraums,and gave a design on the laser arrangement for ignition octahedral hohlraums.As a result,the injection angle of laser beams of 50°-60°was proposed as the optimum candidate range for the octahedral spherical hohlraums.We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields,in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport.We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums,the rugby hohlraums and the cylindrical hohlraums,and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive.Up till to now,we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG)laser facilities,including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums,spherical hohlraum energetics on the SGIII prototype laser facility,and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.
文摘The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all weather surface link between the two districts of Ladakh region (Kargil and Leh). The area under investigation experiences high vehicular traffic, particularly between March and August, as in the remaining months the Kargil and Leh districts?remain cutoff?from each other due to bad weather. In recent years, frequent occurrences of slope failures along the highway primarily affect the smooth functioning of the traffic movement which severely affects the life of the people of the area. Strategically, this road network is very important and plays a significant role in transportation and other activities. In order to ensure the stability of road network in the area, it becomes extremely important to understand the triggering mechanism of these failures. The present study made an attempt in this direction and the Slope Mass Rating (SMR) method has been used for slope stability analysis at different locations. The stability of the slopes was also assessed using kinematic analysis conjointly with SMR to identify the types of failure and its potential failure directions associated with each slope. The result obtained after calculating RMR from the selected facets ranges from 11 to 89 with lower values indicating presence of potentially unstable areas. Results have shown that in a total of 20 facets, 65.28% belong to wedge failure, 22.26%?belong to toppling failure and 12.45% belong to plane failure.
