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Recent nanotechnology advances enable fabrication of layered structures with controllable inter-layer gap, giving the ultra-violet (UV) lasers access to solid-state plasmas which can be used as medium for electron acceleration. By using a linearly polarized 3 fs-long laser pulse of 100 nm wavelength and 10 21 W/cm 2 peak intensity, we show numerically that electron bunches can be accelerated along a stack of ionized graphene layers. Particle-In-Cell (PIC) simulations reveal a new self-injection mechanism based on edge plasma oscillations, whose amplitude depends on the distance between the graphene layers. Nanometre-size electron ribbons are electrostatically catapulted into buckets of longitudinal electric fields in less than 1 fs, as opposed to the slow electrostatic pull, common to laser wakefield acceleration (LWFA) schemes in gas-plasma. Acceleration then proceeds in the blowout regime at a gradient of 4.79 TeV/m yielding a 0.4 fs-long bunch with a total charge in excess of 2.5 pC and an average energy of 6.94 MeV, after travelling through a graphene target as short as 1.5 μ m. These parameters are unprecedented within the LWFA research area and, if confirmed experimentally, may have an impact on fundamental femtosecond research. [ABSTRACT FROM AUTHOR]

We report the overdense electron acceleration and dense gamma ray emission via the use of two continuous laser pulses irradiating near critical density plasma. Thanks to the ion channel formed behind the first laser pulse, the leading laser beam is well focused to a higher intensity. As a result, the noticeable electron re-injection and ion focusing when one laser incident is significantly suppressed in the two-consecutive- lasers scheme, efficiently improved the electron acceleration process. Moreover, owing to the stronger laser field and the higher electron energy, the probability rate of the accelerated electron emitting Îł -rays is considerably enhanced. In this regime, the laser intensity is reduced from 1 Ă— 10 23 to 4 Ă— 10 22 W cmâˆ'2 with the competitive density of generated gamma rays. [ABSTRACT FROM AUTHOR]

Plasma wakefields driven by high power lasers or relativistic particle beams can be orders of magnitude larger than the fields produced in conventional accelerating structures. Since the plasma wakefield is composed not only of accelerating but also of decelerating phases, this paper proposes to utilize the strong decelerating field induced by a laser pulse in the plasma to absorb the beam energy, in a scheme known as the active plasma beam dump. The design of this active plasma beam dump has considered the beam output by the EuPRAXIA facility. Analytical estimates were obtained, and compared with particle-in-cell simulations. The obtained results indicate that this active plasma beam dump can contribute for more compact, safer, and greener accelerators in the near future. [ABSTRACT FROM AUTHOR]