共查询到20条相似文献,搜索用时 109 毫秒
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给出理想条件下聚光镜焦平面上单个μ子大气契仑柯夫光像的理论结果.简要地介绍在标定第二代大气契仑柯夫光成像望远镜中的应用. 相似文献
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采用紧聚焦的超强短脉冲激光与固体通道靶相互作用是获得大电量、高准直相对论电子束的一种有效方式。实验中由于激光预脉冲烧蚀靶壁产生预等离子体会膨胀、填充到真空通道中,从而导致电子束品质发生变化。采用二维PIC粒子模拟程序研究了通道靶中填充预等离子体的电子加速过程。模拟结果显示,在功率密度为5.0×10^(20W/cm^(2))的超强短脉冲激光条件下,通道中填充一定密度的等离子体时激光场优先与低密度等离子体相互作用,激光脉冲与通道壁的相互作用减弱,电子加速机制由纵向场主导的真空电子加速转变为横向电场主导的等离子体电子加速,产生电子束具有更大的电荷量,但能量降低,发散角增大。 相似文献
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用2.5维粒子模拟程序模拟了超强激光与等离子体的相互作用过程,发现超强激光可以通过J×B加热机制加速电子并引起电荷分离,从而产生很强的静电场并形成电场势阱,电子在静电场势阱中振荡,被多次加速,使得高速电子被甩出势阱,进而增强电荷分离,然后静电场结构被破坏,静电势能传给电子。在此过程中,电子在此阱中作局域振荡,并且被J×B机制多次加速,激光的能量会有效地传给电子,使电子能量高达10MeV。这是一种新的电子加热机制,称之为局域振荡电子加热机制。 相似文献
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利用X射线在探针中的康普顿散射以及电子在光纤中的契仑柯夫效应可以构成光纤X射线探针和测量系统,本文对此做了理论和实验研究,推导了光纤探针的灵敏度公式,给出了计算结果,并做了实验标定,讨论了光纤探针测量系统的构成,测量的动态范围和响应时间。 相似文献
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The main feature of the examined cyclic induction accelerator is the separation of control and accelerating electromagnetic fluxes. The control magnetic field is formed by analogy with the magnetic field of a weakly focusing synchrotron, and the accelerating vortex electric field is generated by electromagnetic cores – inductors. Such a design of the cyclic induction accelerator allows the active steel volume and the power of a supply unit to be reduced significantly, and the separation of control and accelerating magnetic fluxes allows the energy lost by particles by synchrotron emission to be compensated using a relatively simple method. Recent investigations have demonstrated that in this accelerator, electrons can be accelerated to energies exceeding 300 MeV. 相似文献
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É. S. Masunov 《Technical Physics》2001,46(11):1433-1436
The use of high-frequency field harmonics nonsynchronous with the beam for focusing and accelerating charged particles in periodic resonant structures is discussed. Conditions for effective acceleration of particles in the transverse and longitudinal fields of a high-frequency undulator are found. A specific implementation of particle focusing and acceleration, as well as the numerical calculation of deuterium ion dynamics in a new type of a linear accelerator, are reported. 相似文献
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Beam instabilities in an accelerator with focusing of an axisymmetric accelerating field are considered for deviation of the field from axial symmetry. The effect is evaluated quantitatively for an accelerator with phase-variable focusing produced by a two-conductor resonator. It is shown that at the resonances the effective beam radius can increase substantially, even for a short accelerator about 1 m in length.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 10–13, December, 1987. 相似文献
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Z. Sedláček 《Czechoslovak Journal of Physics》1964,14(2):106-115
The paper deals with an investigation into the equilibrium orbits of charged particles in one variant of the isochronous ultrarelativistic cyclotron, i.e. accelerator with time independent, axially increasing magnetic field and strong focusing for accelerating charged particles at constant orbital time. The author finds phenomena well known from the theory of oscillations of non-linear mechanical systems (in a certain region of the parameters of a magnetic field there exist substantially two equilibrium orbits, while in another region none exist), which have no analogy in other accelerators. A variant of the ultrarelativistic cyclotron with axially scalloped equilibrium orbit is proposed. 相似文献
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Overview of plasma-based accelerator concepts 总被引:2,自引:0,他引:2
Esarey E. Sprangle P. Krall J. Ting A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(2):252-288
An overview is given of the physics issues relevant to the plasma wakefield accelerator, the plasma beat-wave accelerator, the laser wakefield accelerator, including the self-modulated regime, and wakefield accelerators driven by multiple electron or laser pulses. Basic properties of linear and nonlinear plasma waves are discussed, as well as the trapping and acceleration of electrons in the plasma wave. Formulas are presented for the accelerating field and the energy gain in the various accelerator configurations. The propagation of the drive electron or laser beams is discussed, including limitations imposed by key instabilities and methods for optically guiding laser pulses. Recent experimental results are summarized 相似文献
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Richard Klíma 《Czechoslovak Journal of Physics》1958,8(4):404-410
A theory of phase motion in a synchronous circular accelerator is derived for the case that, in addition to the accelerating component of a high-frequency field, a component acts on a particle which deforms the path of the particle. For an accelerator with constant period of revolution and fixed magnetic field the result is asymptotic focusing of the particles to a certain phase s.In conclusion the author thanks Dr. M. Seidl for suggesting this paper and for many remarks during its elaboration. He also thanks members of the seminary of the sector of accelerators for criticisn and, last but not least, L. Krlín for friendly cooperation. 相似文献
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Hidding B Pretzler G Rosenzweig JB Königstein T Schiller D Bruhwiler DL 《Physical review letters》2012,108(3):035001
Beam-driven plasma wakefield acceleration using low-ionization-threshold gas such as Li is combined with laser-controlled electron injection via ionization of high-ionization-threshold gas such as He. The He electrons are released with low transverse momentum in the focus of the copropagating, nonrelativistic-intensity laser pulse directly inside the accelerating or focusing phase of the Li blowout. This concept paves the way for the generation of sub-μm-size, ultralow-emittance, highly tunable electron bunches, thus enabling a flexible new class of an advanced free electron laser capable high-field accelerator. 相似文献
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Bunching, acceleration, and transverse focusing of intense ion beams in an undulator linac are considered. Such an accelerator features the absence of an rf field harmonic synchronous with the beam. A 3D equation of motion in the Hamiltonian form is derived in the smooth approximation, and the general conditions for ion beam acceleration and transverse focusing in the undulator linac are formulated. Basic analytical results are compared with the results of numerical simulation of the beam dynamics in the polyharmonic field of an accelerating cavity. 相似文献
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The surface resistance of copper is studied in the region of classical and anomalous skin effect. The surface resistance gain (equal to the ratio of the surface resistances of copper at room and helium temperatures) is determined as a function of the electromagnetic field frequency. It is shown that the gain has an inverse power dependence on frequency. The frequencies at which the gain for copper is equal to 10 are determined. It is found that high-frequency power losses in the walls of the accelerating structure of the accelerator, which is prepared from nonsuperconducting metals at T ≥ 4.2 K, can be reduced by more than an order of magnitude as compared to an accelerating structure operating at room temperature. This confirms the possibility of developing a high-efficiency accelerator. 相似文献
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XU JIAN-MING 《中国物理C(英文版)》1982,6(3):378-380
In this paper, it is pointed out that in the phase adjusted focusing laser accelerator,particles are accelerated by "slow wave" (synchronizing with the accelerated particles)but not "fast wave". (waves whose phase velocity is faster than the speed of light).Some measures should be taken so as to get stability in both longitudinal and transversemotion. 相似文献