共查询到20条相似文献,搜索用时 62 毫秒
1.
Self-Injection and Acceleration of Monoenergetic Electron Beams from Laser Wakefield Accelerators in a Highly Relativistic Regime 下载免费PDF全文
H.Yoshitama ;T.Kameshima ;谷渝秋 ;郭仪 ;焦春晔 ;刘红杰 ;彭翰生 ;唐传铭 ;王小东 ;温贤伦 ;温天舒 ;吴玉迟 ;张保汉 ;朱启华 ;黄晓军 ;安维民 ;黄文会 ;唐传祥 ;林郁正 ;王小东 ;陈黎明 ;H.Kotaki ;M.Kando ;K.Nakajima 《中国物理快报》2008,25(8):2938-2941
Self-injection and acceleration of monoenergetic electron beams from laser wakefield accelerators are first investigated in the highly relativistic regime, using 100 TW class, 27 fs laser pulses. Quasi-monoenergetic multi- bunched beams with energies as high as multi-hundredMeV are observed with simultaneous measurements of side-scattering emissions that indicate the formation of self-channelfing and self-injection of electrons into a plasma wake, referred to as a 'bubble'. The three-dimensional particle-in-cell simulations confirmed multiple self-injection of electron bunches into the bubble and their beam acceleration with gradient of 1.5 GeV/cm. 相似文献
2.
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
3.
We use three-dimensional particle-in-cell simulations to study laser wake field acceleration (LWFA) at highly relativistic
laser intensities. We observe ultra-short electron bunches emerging from laser wake fields driven above the wave-breaking
threshold by few-cycle laser pulses shorter than the plasma wavelength. We find a new regime in which the laser wake takes
the shape of a solitary plasma cavity. It traps background electrons continuously and accelerates them. We show that 12-J,
33-fs laser pulses may produce bunches of 3×1010 electrons with energy sharply peaked around 300 MeV. These electrons emerge as low-emittance beams from plasma layers just
700-μm thick. We also address a regime intermediate between direct laser acceleration and LWFA, when the laser-pulse duration
is comparable with the plasma period.
Received: 12 December 2001 / Published online: 14 March 2002 相似文献
4.
M. Kando Y. Fukuda H. Kotaki J. Koga S. V. Bulanov T. Tajima A. Chao R. Pitthan K. -P. Schuler A. G. Zhidkov K. Nemoto 《Journal of Experimental and Theoretical Physics》2007,105(5):916-926
We suggest a novel method for the injection of electrons into the acceleration phase of particle accelerators, producing low-emittance
beams appropriate even for the demanding high-energy linear collider specifications. We discuss the injection mechanism into
the acceleration phase of the wakefield in a plasma behind a high-intensity laser pulse, which takes advantage of the laser
polarization and focusing. The scheme uses the structurally stable regime of transverse wakewave breaking, when the electron
trajectory self-intersection leads to the formation of a flat electron bunch. As shown in three-dimensional particle-in-cell
simulations of the interaction of a laser pulse elongated in the transverse direction with an underdense plasma, the electrons
injected via the transverse wakewave breaking and accelerated by the wakewave perform betatron oscillations with different
amplitudes and frequencies along the two transverse coordinates. The polarization and focusing geometry lead to a way to produce
relativistic electron bunches with an asymmetric emittance (flat beam). An approach for generating flat laser-accelerated
ion beams is briefly discussed.
The text was submitted by the authors in English. 相似文献
5.
A.G. Khachatryan M.J.H. Luttikhof F.A. van Goor K.-J. Boller 《Applied physics. B, Lasers and optics》2007,86(1):41-47
For the purpose of laser wakefield acceleration, it turns out that the injection of electron bunches longer than the plasma wavelength can also generate accelerated femtosecond bunches with a relatively low energy spread. This is of great interest because such injecting bunches can be provided, e.g., by photo cathode rf linacs. Here we show that when an e-bunch is injected into the wakefield, it is important to take into account the interaction of the injected bunch with the laser pulse in the vacuum region located in front of the plasma. We show that at low energies of the injected bunch, this leads to ponderomotive scattering of the bunch and results in a significant drop of the collection efficiency. For certain injection energies the ponderomotive scattering may result in a smaller energy spread in the accelerated bunch. It is found that the injection position in the laser wakefield plays an important role. Higher collection efficiency can be obtained for certain injection energies, when the bunch is injected in plasma at some distance from the laser pulse; the energy spread, however, is typically larger in this case. We also estimate the minimum trapping energy for the injected electrons and the length of the trapped bunch. PACS 52.38.Kd; 41.75.Jv; 41.85.Ar 相似文献
6.
7.
8.
Electron acceleration in plasma driven by circularpolarized ultraintense laser with asymmetric pulse are investigatedanalytically and numerically in terms of oscillation-center Hamiltonian formalism. Studies include wakefield acceleration, which dominates in blow-out or bubble regime and snow-plow acceleration which dominates in supra-bubble regime. By a comparison with each other it is found that snow-plow acceleration has lower acceleration capability. In wakefield acceleration, there exists an obvious optimum pulse asymmetry or/and pulse lengths that leads to the high net energy gain while in snow-plow acceleration it is insensitive to the pulse lengths. Power and linear scaling laws for wakefield and snow-plow acceleration respetively are observed from the net energy gain depending on laser field amplitude. Moreover, there exists also an upper and lower limit on plasma density for an effective acceleration in both of regimes. 相似文献
9.
The acceleration of ions in the interaction of high intensity laser pulses with overdense plasmas is investigated with particle-in-cell simulations. For circular polarization of the laser pulses, high-density ion bunches moving into the plasma are generated at the laser-plasma interaction surface. A simple analytical model accounts for the numerical observations and provides scaling laws for the ion bunch energy and generation time as a function of pulse intensity and plasma density. 相似文献
10.
S. V. Kuznetsov 《Physics of Particles and Nuclei Letters》2018,15(7):728-731
The formation and acceleration of electron bunches resulting from the self-injection of electrons into the wake wave from the laser pulse moving through a sharp plasma boundary are investigated in one-dimensional geometry. It is shown that electron trapping in the accelerating wakefield is governed by the electron energy and has a threshold character. The acceleration of the trapped bunch is numerically simulated. 相似文献
11.
Shvets G. Fisch N.J. Pukhov A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(4):1194-1201
The nonlinear interaction between counterpropagating laser beams in a plasma results in the generation of large (enhanced) plasma wakes. The two beams need to be slightly detuned in frequency, and one of them has to be ultrashort (shorter than a plasma period). Thus produced wakes have a phase velocity close to the speed of light and can be used for acceleration and compression of charged bunches, The physical mechanism responsible for the enhanced wake generation is qualitatively described and compared with the conventional laser wakefield mechanism. We also demonstrate that depending on the sign of the frequency difference between the lasers, the enhanced wake can be used as a “snow-plow” to accelerate and compress either positively or negatively charged bunches. This ability can be used in an electron-positron injector 相似文献
12.
O. Jansen T. Tückmantel A. Pukhov 《The European physical journal. Special topics》2014,223(6):1017-1030
Electron acceleration in the laser-plasma bubble appeared to be the most successful regime of laser wake field acceleration in the last decade. The laser technology became mature enough to generate short and relativistically intense pulses required to reach the bubble regime naturally delivering quasi-monoenergetic bunches of relativistic electrons. The upcoming laser technology projects are promising short pulses with many times more energy than the existing ones. The natural question is how will the bubble regime scale with the available laser energy. We present here a parametric study of laser-plasma acceleration in the bubble regime using full three dimensional particle-in-cell simulations and compare numerical results with the analytical scalings from the relativistic laser-plasma similarity theory. 相似文献
13.
Kallos E Katsouleas T Kimura WD Kusche K Muggli P Pavlishin I Pogorelsky I Stolyarov D Yakimenko V 《Physical review letters》2008,100(7):074802
A plasma-wakefield experiment is presented where two 60 MeV subpicosecond electron bunches are sent into a plasma produced by a capillary discharge. Both bunches are shorter than the plasma wavelength, and the phase of the second bunch relative to the plasma wave is adjusted by tuning the plasma density. It is shown that the second bunch experiences a 150 MeV/m loaded accelerating gradient in the wakefield driven by the first bunch. This is the first experiment to directly demonstrate high-gradient, controlled acceleration of a short-pulse trailing electron bunch in a high-density plasma. 相似文献
14.
Leemans W.P. Siders C.W. Esarey E. Andreev N.E. Shvets G. Mori W.B. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(2):331-342
A design study has been carried out for a second-generation experiment on laser guiding and wakefield excitation in a channel. From simple scaling laws for the wakefield amplitude, dephasing length, the relativistic group velocity factor γg, and energy gain with and without guiding, we find that the parameter regime for a compact single stage GeV accelerator favors laser systems producing short pulses (10 fs⩽τ⩽100 fs), each containing an energy on the order of 100 mJ to a few J's. Taking the dephasing length as the maximum acceleration distance, plasma channels with lengths of 1-10 cm and densities of 1017-1019 cm-3 need to be produced; whereas the design study has been primarily concerned with diffraction and channel guiding, dephasing and depletion limits, and linear wakefield theory, aspects of the effect of the plasma wave on the evolution of the laser pulse are discussed. We find that transverse and longitudinal pulse distortions could indeed affect the generated plasma wave phase velocity and amplitude, and hence may limit the achievable energy gains over the one-dimensional (1-D) linear estimates. Some issues for experiments on prototype small accelerators (100 MeV-1 GeV, cm scale) are also discussed 相似文献
15.
Ahmed M. M. Elsied Nasr A. M. Hafz LI Song Mohammad Mirzaie Thomas Sokollik ZHANG Jie 《中国物理C(英文版)》2015,39(6):067003-067003
At Shanghai Jiao Tong University (SJTU) we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams of reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared. 相似文献
16.
Z. M. Sheng W. M. Wang R. Trines P. Norreys M. Chen J. Zhang 《The European physical journal. Special topics》2009,175(1):49-55
Numerical studies are conducted on the electron injection into the first acceleration bucket of a laser wakefield by a weak
counter-propagating laser pulse. It is shown that there are two injection mechanisms involved during the colliding laser interaction,
the collective injection and stochastic injection. They are caused by the time-averaged ponderomotive force push and stochastic
acceleration in the interfering fields, respectively. The threshold amplitude of the injection laser pulse is estimated for
the occurrence of electron injection, which is close to that for stochastic acceleration and depends weakly upon the plasma
density. The trapping of a large number of injection electrons can result in significant decay of the laser wakefield behind
the first wave bucket. 相似文献
17.
E. A. Govras V. Yu. Bychenkov A. V. Brantov 《Journal of Experimental and Theoretical Physics》2012,114(5):748-767
As applied to the problem of laser-induced ion acceleration, we have developed a theory for the expansion of a completely ionized thin two-ion-species target in the regime of a Coulomb explosion typical of the interaction of relativistically intense femtosecond laser pulses with nanofoils. Based on this theory and a simple numerical model, we have studied the generation of bunches of quasi-monoenergetic light ions and found their characteristics as a function of target parameters. We have performed a comparative analysis of the acceleration of light ions uniformly distributed in the target and concentrated in the form of a thin layer. For the production of high-quality accelerated ion beams, we have found optimal conditions that were qualitatively confirmed by our three-dimensional kinetic simulations of the laser pulse-thin target interaction. 相似文献
18.
19.
A. D. Debus M. Bussmann M. Siebold A. Jochmann U. Schramm T. E. Cowan R. Sauerbrey 《Applied physics. B, Lasers and optics》2010,100(1):61-76
We present a novel high-yield Thomson scattering geometry that takes advantage of compact electron bunches, as available in
advanced, low-emittance linear accelerators or laser wakefield accelerators. In order to avoid the restrictions on the X-ray
photon yield imposed by the Rayleigh limit, we use ultrashort, pulse-front tilted laser pulses in a side-scattering geometry.
Such a traveling-wave setup allows an overlap of electron and laser beams, even after propagating over distances much longer
than the Rayleigh length. Experimental designs are discussed and optimized for different scattering angles. Specifically,
to minimize group delay dispersion at large scattering angles >10°, we propose the use of varied-line spacing (VLS) gratings
for spatio-temporal laser pulse shaping. Compared to head-on (180°) Thomson scattering, interaction lengths are in the centimeter
to meter range and photon numbers for ultrashort X-ray pulses can increase by several orders of magnitudes. 相似文献
20.
Schreiber J Bellei C Mangles SP Kamperidis C Kneip S Nagel SR Palmer CA Rajeev PP Streeter MJ Najmudin Z 《Physical review letters》2010,105(23):235003
We present complete experimental characterization of the temporal shape of an intense ultrashort 200-TW laser pulse driving a laser wakefield. The phase of the pulse was uniquely measured by using (second-order) frequency-resolved optical gating. The pulses are asymmetrically compressed and exhibit a positive chirp consistent with the expected asymmetric self-phase-modulation due to photon acceleration or deceleration in a relativistic plasma wave. The measured pulse duration decreases linearly with increasing length and density of the plasma, in quantitative agreement with the intensity-dependent group velocity variation in the plasma wave. 相似文献