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With the advancement of high-power UV laser technology, the use of nanostructures for particle acceleration attracts renewed interest due to its possibility of achieving TV/m accelerating gradients in solid state plasmas. Electron acceleration in ionized materials such as carbon nanotubes and graphene is currently considered as a potential alternative to the usual laser wakefield acceleration (LWFA) schemes. An evaluation of the suitability of a graphene target for LWFA can be carried out using an effective density model, thus replacing the need to model each layer. We present a 2D evaluation of the longitudinal electric field driven by a short UV laser pulse in a multi-layer graphene structure, showing that longitudinal fields of ~5 TV/m are achievable., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

This work presents a study on laser wakefield electron acceleration in the self-modulated regime (SM-LWFA) using 50-fs laser pulses with energy on the mJ scale, at λ = 0.8 µm, impinging on a thin H2 gas jet. Particle-in-cell simulations were performed using laser peak powers ranging from sub-terawatt to a few terawatts and plasma densities varying from the relativistic self-focusing threshold up to values close to the critical density. The differences in the obtained acceleration processes are discussed. Results show that bunched electron beams with full charge on the nC scale and kinetic energy in the MeV range can be produced and configurations with peak density in the range 0.5–5 × 1020 atoms/cm3 generate electrons with maximum energies. In this range, some simulations generated quasimonoenergetic bunches with ∼0.5% of the total accelerated charge and we show that the beam characteristics, process dynamics, and operational parameters are close to those expected for the blowout regime. The configurations that led to quasimonoenergetic bunches from the sub-TW SM-LWFA regime allow the use of laser systems with repetition rates in the kHz range, which can be beneficial for practical applications.

In this work, particle-in-cell simulations were carried out to investigate the role of the down-ramp length of a H\textsubscript{2} gas jet in accelerating electrons ionized by the laser pulse. The laser and plasma density were chosen so that the system is operating in the self-modulated regime. Preliminary results show how the down-ramp length can control the injection of electrons in the first bubble induced in the plasma by the laser pulse., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

In this work, the current status on the development of a laser plasma accelerator at the Nuclear and Energy Research Institute (Instituto de Pesquisas Nucleares e Energéticas, IPEN/CNEN), in São Paulo, Brazil, is presented. Short pulses to be produced by an under-development near-TW, kHz laser system will be used to ionize a gas jet, with a density profile designed to optimize the self-injection of plasma electrons. The same laser pulse will also drive a plasma wakefield, which will allow for electron acceleration in the self-modulated regime. The current milestone is to develop the experimental setup, including electron beam and plasma diagnostics, required to produce electron bunches with energies of a few MeV. Once this has been achieved, the next milestone is to produce beams with energies higher than 50 MeV. Besides kickstarting the laser wakefield accelerator (LWFA) technology in Brazil, this project aims to pave the way for conducting research on the production of radioisotopes by photonuclear reactions, triggered by LWFA-accelerated beams., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The active plasma beam dump utilizes a laser to generate a plasma wakefield and decelerate an externally injected beam to low energy. We use the particle-in-cell code "Smi-lei" for the investigation of electron beam energy loss in plasma. In this research work, we optimize the laser and plasma parameters to investigate the active plasma beam dump scheme. In doing so, most of the beam energy will be deposited in the plasma. The optimization strategy for the beam energy loss in plasma is presented., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

In order to make a full use of the whole proton bunch to drive large amplitude plasma wakefields and suppress the uncontrolled growth of any possible instabilities at the head of the proton bunch, the AWAKE Run 2 experiment plans to use an electron bunch to seed the formation of the proton bunch self-modulation. Additionally, a density step in the plasma channel will be used to freeze the selfmodulation process to keep the wakefield amplitude. In this work, numerical simulations performed with FBPIC are used to investigate the electron seeded proton self-modulation and the effect of the plasma density step as well., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

In this work, particle-in-cell simulations were carried out to investigate the dynamics of a laser pulse propagating along a H₂ gas jet. The laser-driven wakefield and the density of ionized electrons are analyzed during the pulse propagation through the gas jet. The laser and plasma quantities were chosen in order to have the system operating in the self-modulated regime. Results show how the self-modulation fragments the laser pulse, originating higher-amplitude pulses that can induce bubble formation with wave-breaking and particle injection., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

A semi-analytical 1D model is derived for the total energy loss of an electron beam with Gaussian density profile undergoing a passive plasma beam dump. The model is compared to a previous one, obtained for a half-sine longitudinal density profile. It is shown that both models agree if the beam density profiles are properly matched, and if their sizes are small in comparison to the length of wakefield decelerating length. The beam energy obtained from both models is compared to 1D PIC simulation results., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

In this work the nonlinear relativistic propagation of intense lasers in plasmas is investigated. It is known that, under appropriate conditions, the ponderomotive force associated with the laser envelope can excite large amplitude electron waves (wakefields), which can be of interest for particle acceleration schemes. Numerical solutions showing some of the possible behaviors of this system are presented and compared to analytical ones, obtained through an effective potential approach using a one-dimensional Lagrangian formalism., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

This work presents a study about a passive dumping scheme applied to the beam generated by the accelerator stage of the EuPraxia experiment. Particle-in-cell simulations have been carried out and its results are compared with analytical estimates, showing a reasonable agreement., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia