共查询到20条相似文献,搜索用时 15 毫秒
1.
X. Q. Yan T. Tajima M. Hegelich L. Yin D. Habs 《Applied physics. B, Lasers and optics》2010,98(4):711-721
A theory for ion acceleration by ultrashort laser pulses is presented to evaluate the maximum ion energy in the interaction
of ultrahigh contrast (UHC) intense laser pulses with a nanometer-scale foil. In this regime, the ion energy may be directly
related to the laser intensity and subsequent electron dynamics. This leads to a simple analytical expression for the ion
energy gain under the laser irradiation of thin targets. Significantly higher energies for thin targets than for thicker targets
are predicted. The theory is concretized with a view to compare with the results and their details of recent experiments. 相似文献
2.
A new method for improving the efficiency of laser drilling has been developed. Two synchronized free-running laser pulses
from a tandem-head Nd:YAG laser are capable of drilling through 1/8-in-thick stainless-steel targets at a stand-off distance
of 1 m without gas-assist. The combination of a high-energy laser pulse for melting with a properly tailored high-intensity
laser pulse for liquid expulsion results in the efficient drilling of metal targets. We argue that the improvement in drilling
is due to the recoil pressure generated by rapid evaporation of the molten material by the second laser pulse.
Received: 29 August 2000 / Accepted: 18 December 2000 / Published online: 3 April 2001 相似文献
3.
Imaging laser radar can give intensity and range images, which provide integrated 3-dimensional (3D)information about objects. However, dropouts and range anomalies exacerbate range images, which makes their background cluttered and target blurred. For background suppression, a new algorithm that combines intensity image and its mean is presented. By using this algorithm to process actual laser radar range images, most background noises are suppressed. According to range anomalies characteristics, multitemplate selection order mean filtering algorithm is presented and used for actual ladar range images where the distance between two targets is 77 m. This algorithm obtains the clear range image in which the interval of two objects is 75 m. The result shows that the processing algorithm is correct and effective. 相似文献
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新概念高能激光武器的研究与发展已有四十多年的历史。第一代高能激光武器主要采用连续波化学激光器,其输出功率可达百万瓦。第二代高能激光武器主要采用了波长更短的节能固体激光器件,其输出功率为100kW。与第一代高能化学激光武器采用超高能量直接烧毁杀伤目标不同,第二代高能固体激光武器寻求节能型杀伤方式,即以最小程度的破坏来实现致命杀伤的效果。随着高能激光武器的发展和实战部署,作为高能激光武器核心的高能激光系统总体性能参数(能量/功率、激光波形、光束质量、近场和远场的强度分布、光束指向稳定性、光谱和偏振特性等)的计量和测试显得尤为重要。文中围绕新概念高能激光武器的历史、研究现状和未来发展展开论述。高能激光武器系统的研制对强激光光学计量检测技术提出的新要求和挑战有助于推进强激光光学计量检测技术的发展。 相似文献
6.
In the absorption chamber of a high-energy laser energy meter, water is directly used as an absorbing medium and the interaction of the high-power laser and the water flow can produce a variety of physical phenomena such as phase transitions. The unit difference method is adopted to deduce the phase transition model for water flow irradiated by a high-energy laser. In addition, the model is simulated and verified through experiments. Among them, the experimental verification uses the photographic method, shooting the distribution and the form of the air mass of water flow in different operating conditions, which are compared with the simulation results. The research shows that it is achievable to reduce the intensity of the phase transition by increasing the water flow, reducing the power intensity of the beam, shortening the distance the beam covers, reducing the initial water temperature or adopting a shorter wavelength laser. The study's results will provide the reference for the design of a water-direct-absorption-type high-energy laser energy meter as well as an analysis of the interaction processes of other similar high-power lasers and water flow. 相似文献
7.
A. A. Baldin A. I. Berlev V. Bradnova A. V. Butenko A. N. Fedorov I. V. Kudashkin 《Physics of Particles and Nuclei Letters》2016,13(3):378-383
The results of the development and testing of elements of a test bench for investigating the impact of accelerated particle beams on biological objects, electronics, and other targets are presented. The systems for beam monitoring and target positioning were tested on extracted argon beams in the framework of experiments on studying the radiation hardness of electronic components. 相似文献
8.
Fronya A. A. Borisenko N. G. Sahakyan A. T. Puzyrev V. N. Starodub A. N. Yakushev O. F. 《Physics of Atomic Nuclei》2019,82(10):1429-1432
The results of a laser—matter interaction experiment are presented in the paper. Low-density volume-structured material (cellulose triacetate) is used as a target in the experiments. Low-density materials are of interest for both fundamental and applied research. The information on how the parameters of the target and laser radiation influence the penetration of laser radiation through the generated plasma layer is generalized. The energy, spatial, spectral, and temporal characteristics of the plasma of low-density cellulose triacetate targets are analyzed.
相似文献9.
The use of a TV camera with a standard pyroelectric tube for imaging continuous submillimeter (submm) waves is described. The spectral sensitivity of such pyroelectric vidicon has been measured. The results of experiments on diffraction and interference using submm laser radiation are presented. For the first time, submm images of different objects have been obtained with the aid of a pyroelectric vidicon. It has been shown that a pyroelectric TV camera can be effectively employed in various laser studies as well as in submm imagery technique. 相似文献
10.
V. S. Belyaev P. A. Batishchev V. V. Bolshakov K. S. Elkin G. F. Karabadzhak D. V. Kovkov A. P. Matafonov G. G. Raykunov R. A. Yakhin S. A. Pikuz I. Yu. Skobelev A. Ya. Faenov V. E. Fortov V. P. Krainov V. B. Rozanov 《Physics of Atomic Nuclei》2013,76(4):404-422
The results of work on choosing and substantiating promising lines of research in the realms of laboratory astrophysics with the aid of powerful lasers are presented. These lines of research are determined by the possibility of simulating, under laboratory conditions, problematic processes of presentday astrophysics, such as (i) the generation and evolution of electromagnetic fields in cosmic space and the role of magnetic fields there at various spatial scales; (ii) the mechanisms of formation and evolution of cosmic gamma-ray bursts and relativistic jets; (iii) plasma instabilities in cosmic space and astrophysical objects, plasma jets, and shock waves; (iv) supernova explosions and mechanisms of the explosion of supernovae featuring a collapsing core; (v) nuclear processes in astrophysical objects; (vi) cosmic rays and mechanisms of their production and acceleration to high energies; and (vii) astrophysical sources of x-ray radiation. It is shown that the use of existing powerful lasers characterized by an intensity in the range of 1018–1022 W/cm2 and a pulse duration of 0.1 to 1 ps and high-energy lasers characterized by an energy in excess of 1 kJ and a pulse duration of 1 to 10 ns makes it possible to perform investigations in laboratory astrophysics along all of the chosen promising lines. The results obtained by experimentally investigating laser plasma with the aid of the laser facility created at Central Research Institute of Machine Building (TsNIIMash) and characterized by a power level of 10 TW demonstrate the potential of such facilities for performing a number of experiments in the realms of laboratory astrophysics. 相似文献
11.
J. Galy D. J. Hamilton C. Normand 《The European physical journal. Special topics》2009,175(1):147-152
In the last decade or so, an evolution in experimental relativistic laser-plasma physics has led to highly sophisticated lasers
which are now capable of generating ultra-short pulses and can be focused to intensities in excess of 1021 W cm-2. The laser interaction with solid or gas targets can generate collimated beams of highly energetic electrons, protons and
ions. These high-intensity laser systems, therefore, turn out to be versatile and powerful sources of radiation and high-energy
particles, without recourse to large-scale facilities such as nuclear reactors or particle accelerators. The potential to
induce various kinds of nuclear reactions with laser-induced radiation fields has been demonstrated at several laboratories
in recent years. The present paper lays out a comprehensive overview of nuclear reactions induced by high-intensity laser
matter interactions. Mechanisms for electron, proton and ion acceleration, in addition to secondary bremsstrahlung, positron
and neutron production, are addressed, with a focus on the types of nuclear reactions that are possible and potential applications.
Discussion of the extrapolation of these processes and applications to the next generation of table-top lasers under construction
is also presented. 相似文献
12.
N. G. Basov B. L. Vasin A. A. Galichii A. E. Danilov B. Yu. Ivanov M. P. Kalashnikov B. V. Kruglov Yu. A. Mikhailov V. P. Osetrov V. N. Puzyrev A. V. Rode S. M. Savchenko G. V. Sklizkov V. M. Solodkov S. I. Fedotov V. A. Tsitovich L. I. Shishkina 《Journal of Russian Laser Research》1983,4(3):205-220
The construction principle and the applicable system are considered for the highpower laser amplifier module of the “Del'fin” facility, intended for spherical heating of thermonuclear targets. Results are presented of investigations of the radiation parameters of the amplifier module under various operating regimes. The system for focusing the laser radiation on the target surfaces is described and the results of experiments on plasma heating by radiation of three composite laser beams, at a laser energy level up to 1 kJ at a flux density up to 1014 W/cm2, are analyzed. 相似文献
13.
J.?C.?Conde P.?González F.?Lusqui?os B.?León 《Applied Physics A: Materials Science & Processing》2009,95(2):465-471
A theoretical approach and qualitative analysis of the changes induced on the surface morphology and the formation of microstructures
on silicon targets irradiated by excimer laser are presented. This study is based on theoretical principles of the laser ablation
process, in particular, on the analysis of the contribution of the laser energy density, which involves the laser beam parameters
and also the physical properties of the target material. For different laser incident angles, the formation of micro-columns
oriented towards the laser incident direction is explained. Moreover, numerical simulations and ablation experiments carried
out with an excimer laser corroborate the theoretical analysis. 相似文献
14.
H. Krüger 《Zeitschrift für Physik A Hadrons and Nuclei》1966,189(3):302-311
The high laser intensity allows colliding-beam Compton scattering experiments of high-energy electrons with the photons of the red ruby laser light by which the latter are transformed intoγ-radiation photons. Detailed calculations are given in this paper for the “average” polarization over the scattered beam and for the energy spectrum of theγ-rays. 相似文献
15.
In an airborne platform adaptive optics application, the inbound (beacon) and outbound (high-energy laser) wavefronts propagate through different regions of the atmosphere at different time instants, that is, spatial and temporal anisoplanatism cannot be neglected. Measurements in an airborne platform system are from the inbound (beacon) wavefront and therefore, the outbound, high-energy laser's wavefront phase distortion Zernike expansion coefficients must be estimated. Once the said estimates are available, these values are used by a linear quadratic regulator to drive the actuators of the deformable mirror. The controller, which consists of a Kalman filter estimator in tandem with the regulator, provides commands to the piezoelectric actuators of the deformable mirror. Thus, the estimated conjugate phase is applied to the mirror and, hence, to the outbound high-energy laser wavefront, such that at the aim point on the target, the high-energy laser wavefront distortion is minimized. In other words, the high-energy laser is correctly pointed to the aim point and the Strehl ratio is maximized. In this way, the correct deformation is applied to the deformable mirror and the benefits of adaptive optics are realized in an airborne platform application. In Part 2 of this paper, the design of the controller, that is, a Kalman filter and regulator, is addressed. The theoretical derivations are validated in extensive simulation experiments. 相似文献
16.
MENG Zhicong ZHANG Guiyan SONG Xiudong JIANG Jianhua LIN Fucheng 《Chinese Journal of Lasers》1997,6(1):91-96
l.IntroductionTheideaofusingahigh-gainactivemediumtoformbrightness-enhancedmicroscofr-.icimageswasproposedmorethan2oyearsago[1:.Introductionofbrightnessamplifierintousua1oPticalsystemwouldPermittoovercomethewellknownrestrictionaccordingtowhichthebrightnessattheoutputoftheopticalsystemcannotexceedthatatthein-put[zJ.SomepulsedmetalvaporlaserssuchasthecopPervaPOrlaser(CVL)havebeenusedasimage-brightnessamplifiersinvariousopticalprojectionsystem[3j-lnthiscase,wecanbenefitfromthattheactivemedium… 相似文献
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本文介绍空腔靶设计的物理思想、及能量吸收特性、X光转换特性和堵腔特性的实验研究方法,给出了实验观察到的一系列物理现象,通过对现象的分析而得出空腔靶的能量吸收和X光转换明显优于平面靶;利用相对孔径较大的聚焦透镜打空腔靶有利于改善靶的能量吸收和转换特性的结论。 相似文献
19.
Plasma expansion into a vacuum 总被引:1,自引:0,他引:1
Mora P 《Physical review letters》2003,90(18):185002
The charge separation effects in the collisionless plasma expansion into a vacuum are studied in great detail. Accurate results are obtained concerning the structure of the ion front, the resultant ion energy spectrum, and more specifically the maximum ion energy. These are of crucial importance for the interpretation of recent experiments, where high-energy ion jets were produced from short pulse interaction with solid targets. 相似文献