排序方式: 共有39条查询结果,搜索用时 15 毫秒
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Ultraintense laser pulses propagating in near-critical density plasmas generate magnetic dipole vortex structures. In the region of decreasing plasma density, the vortex expands both in forward and lateral directions. The magnetic field pressure pushes electrons and ions to form a density jump along the vortex axis and induces a longitudinal electric field. This structure moves together with the expanding dipole vortex. The background ions located ahead of the electric field are accelerated to high energies. The energy scaling of ions generated by this magnetic vortex acceleration mechanism is derived and corroborated using particle-in-cell simulations. 相似文献
33.
High intensity colliding laser pulses can create abundant electron-positron pair plasma [A. R. Bell and J. G. Kirk, Phys. Rev. Lett. 101, 200403 (2008)], which can scatter the incoming electromagnetic waves. This process can prevent one from reaching the critical field of quantum electrodynamics at which vacuum breakdown and polarization occur. Considering the pairs are seeded by the Schwinger mechanism, it is shown that the effects of radiation friction and the electron-positron avalanche development in vacuum depend on the electromagnetic wave polarization. For circularly polarized colliding pulses, these effects dominate not only the particle motion but also the evolution of the pulses. For linearly polarized pulses, these effects are not as strong. There is an apparent analogy of these cases with circular and linear electron accelerators to the corresponding constraining and reduced roles of synchrotron radiation losses. 相似文献
34.
Romagnani L Bigongiari A Kar S Bulanov SV Cecchetti CA Esirkepov TZh Galimberti M Jung R Liseykina TV Macchi A Osterholz J Pegoraro F Willi O Borghesi M 《Physical review letters》2010,105(17):175002
Slowly evolving, regularly spaced patterns have been observed in proton projection images of plasma channels drilled by intense (?101? W?cm?2) short (~1 ps) laser pulses propagating in an ionized gas jet. The nature and geometry of the electromagnetic fields generating such patterns have been inferred by simulating the laser-plasma interaction and the following plasma evolution with a two-dimensional particle-in-cell code and the probe proton deflections by particle tracing. The analysis suggests the formation of rows of magnetized soliton remnants, with a quasistatic magnetic field associated with vortexlike electron currents resembling those of magnetic vortices. 相似文献
35.
Pirozhkov AS Kando M Esirkepov TZh Gallegos P Ahmed H Ragozin EN Faenov AY Pikuz TA Kawachi T Sagisaka A Koga JK Coury M Green J Foster P Brenner C Dromey B Symes DR Mori M Kawase K Kameshima T Fukuda Y Chen L Daito I Ogura K Hayashi Y Kotaki H Kiriyama H Okada H Nishimori N Imazono T Kondo K Kimura T Tajima T Daido H Rajeev P McKenna P Borghesi M Neely D Kato Y Bulanov SV 《Physical review letters》2012,108(13):135004
We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multiterawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving μJ/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations. 相似文献
36.
Mu J. Esirkepov T. Zh. Valenta P. Jeong T. M. Gu Ya. Koga J. K. Pirozhkov A. S. Kando M. Korn G. Bulanov S. V. 《Physics of Wave Phenomena》2019,27(4):247-256
Physics of Wave Phenomena - The electron density singularity formed at the joining area of relativistic wake wave and bow waves has been proposed as a novel relativistic electron mirror regime to... 相似文献
37.
A method to generate ultrahigh intense electromagnetic fields is suggested, based on the laser pulse compression, carrier frequency upshift, and focusing by a counterpropagating breaking plasma wave, relativistic flying parabolic mirror. This method allows us to achieve the quantum electrodynamics critical field (Schwinger limit) with present-day laser systems. 相似文献
38.
S. V. Bulanov T. Zh. Esirkepov D. Habs F. Pegoraro T. Tajima 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(2):483-507
The paper is devoted to the prospects of using the laser radiation
interaction with plasmas in the laboratory relativistic astrophysics
context. We discuss the dimensionless parameters characterizing the
processes in the laser and astrophysical plasmas and emphisize a similarity
between the laser and astrophysical plasmas in the ultrarelativistic energy
limit. In particular, we address basic mechanisms of the charged particle
acceleration, the collisionless shock wave and magnetic reconnection and
vortex dynamics properties relevant to the problem of ultrarelativistic
particle acceleration. 相似文献
39.
Borghesi M Bulanov SV Esirkepov TZh Fritzler S Kar S Liseikina TV Malka V Pegoraro F Romagnani L Rousseau JP Schiavi A Willi O Zayats AV 《Physical review letters》2005,94(19):195003
Experimental investigations of the late-time ion structures formed in the wake of an ultrashort, intense laser pulse propagating in a tenuous plasma have been performed using the proton imaging technique. The pattern found in the wake of the laser pulse shows unexpectedly regular modulations inside a long, finite width channel. On the basis of extensive particle in cell simulations of the plasma evolution in the wake of the pulse, we interpret this pattern as due to ion modulations developed during a two-stream instability excited by the return electric current generated by the wakefield. 相似文献