M. Moreira
A5038461817- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Particle physics theoretical and experimental studies
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Ionosphere and magnetosphere dynamics
- Dark Matter and Cosmic Phenomena
- Laser-Matter Interactions and Applications
- Pulsed Power Technology Applications
- Plasma Diagnostics and Applications
- Real-time simulation and control systems
- Cyclone Separators and Fluid Dynamics
- Superconducting Materials and Applications
- Nonlinear Dynamics and Pattern Formation
- stochastic dynamics and bifurcation
- Combustion and flame dynamics
- Plasma and Flow Control in Aerodynamics
- Radiation Therapy and Dosimetry
- Gamma-ray bursts and supernovae
University of Lisbon
2019-2024
Ulsan National Institute of Science and Technology
2023
European Organization for Nuclear Research
2018-2021
Instituto Superior de Tecnologias Avançadas
2018-2020
Campbell Collaboration
2020
Google (United States)
2019
Instituto Superior Técnico
2018
Philipps University of Marburg
2017
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, which we observe as filamentation. determine threshold value for ratio between transverse size and skin depth instability to occur. At threshold, outcome of experiment alternates filamentation self-modulation (evidenced by longitudinal modulation into microbunches). Time-resolved images density distribution reveal grows an observable level late along bunch,...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven short, misaligned preceding bunch. Hosing develops the plane misalignment, self-modulation perpendicular plane, at frequencies close to electron frequency, and are reproducible. Development depends on misalignment direction, its growth extent proton charge. Results have main characteristics theoretical model, relevant other plasma-based accelerators represent first characterization...
This paper defines a protocol for geometric description and classification of white eggs chickens using computer vision (CV) artificial neural network (ANN) techniques. For this, 60 were selected their dimensions, volumes surface areas measured pachymeter, immersion method mathematical expressions available in the literature, respectively, to compose reference values. Subsequently, imaged with RGB camera digital images analyzed dedicated algorithm. The estimated parameters compared witness...
A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton can be seeded by wakefields driven preceding electron bunch. timing reproducibility and control are at level small fraction modulation period. With this seeding method, we independently amplitude seed with charge growth rate Seeding leads larger than instability case.
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of long proton bunch in plasma. show experimentally that, with sufficient amplitude [$\ensuremath{\ge}(4.1\ifmmode\pm\else\textpm\fi{}0.4)\text{ }\text{ }\mathrm{MV}/\mathrm{m}$], phase modulation along is reproducible from event event, 3%--7% (of $2\ensuremath{\pi}$) rms variations all bunch. The not lower amplitudes. observe transition between these two regimes. Phase...
We study experimentally the longitudinal and transverse wakefields driven by a highly relativistic proton bunch during self-modulation in plasma. show that wakefields' growth amplitude increase with increasing seed as well charge using maximum radius of distribution measured on screen downstream from externally injecting electrons measuring their final energy. Measurements agree trends predicted theory numerical simulations validate our understanding development self-modulation. Experiments...
Abstract In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from Super Proton Synchrotron at CERN. The angular distribution protons deflected due to SSM is quantitative measure process, which agrees with simulations by two-dimensional (axisymmetric) particle-in-cell code LCODE about 5%. agreement achieved in population scans two selected plasma densities and scan longitudinal density gradient. reached only case wide enough simulation box (several...
In this article, we briefly summarize the experiments performed during first Run of Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research). The final goal AWAKE 1 (2013 - 2018) was to demonstrate that \unit[10-20]{MeV} electrons can be accelerated GeV-energies in a plasma wakefield driven by highly-relativistic self-modulated proton bunch. We describe experiment, outline measurement concept and present results. Last, our plans future.
We study experimentally the effect of linear plasma density gradients on self-modulation a 400\,GeV proton bunch. Results show that positive/negative gradient in/decreases number micro-bunches and relative charge per micro-bunch observed after 10\,m plasma. The measured modulation frequency also in/decreases. With largest positive we observe two frequencies in power spectrum. are consistent with changes wakefields' phase velocity due to adding slow during growth predicted by theory.
Self-modulation is a beam–plasma instability that useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing ratio between initial transverse size of bunch and depth, occurs later along bunch, or not at all, over fixed length because amplitude decreases. show cases for which self-modulation does develop, we introduce simple model discussing conditions it would occur after any length. Changing...
Abstract We briefly compare in numerical simulations the relativistic ionization front and electron bunch seeding of self-modulation a proton plasma. When parameters are such that initial wakefields equal with two methods, evolution maximum longitudinal along plasma is similar. also propose possible seeding/injection scheme using single we will study upcoming works.
The hosing instability poses a feasibility risk for plasma-based accelerator concepts. We show that the growth rate beam in linear regime (which is relevant concepts use long driver) function of centroid perturbation wavelength. demonstrate how this property can be used to damp oscillations by detuning plasma response sufficiently early development instability. also develop new theoretical model evolution hosing. These findings have implications general control an instability's rate.
The vertical plane transverse emittance of accelerated electron bunches at the AWAKE experiment CERN has been determined, using three different methods data analysis. This is a proof-of-principle measurement existing spectrometer to validate technique. Large values geometric emittance, compared that injection beam, are observed ($\sim \SI{0.5}{\milli\metre\milli\radian}$ with $\sim \SI{0.08}{\milli\metre\milli\radian}$), which in line expectations growth arising from plasma density ramps and...
Plasma wakefield dynamics over timescales up to 800 ps, approximately 100 plasma periods, are studied experimentally at the Advanced Wakefield Experiment (AWAKE). The development of longitudinal amplitude driven by a self-modulated proton bunch is measured using external injection witness electrons that sample fields. In simulation, resonant excitation causes electron trajectory crossing, resulting in potential outside boundary as transversely ejected. Trends consistent with presence this...
We present numerical simulations and experimental results of the self-modulation a long proton bunch in plasma with linear density gradients along beam path. Simulation agree reported [F. Braunmller, T. Nechaeva et al. (AWAKE Collaboration), Phys. Rev. Lett. 125, 264801 (2020)]: negative gradients, charge modulated is lower than positive gradients. In addition, modulation frequency varies gradient. show that dephasing wakefields respect to relativistic protons main cause for loss charge. The...
We investigate numerically the detection of self-modulation instability in a virtual detector located downstream from plasma context AWAKE. show that density structures, appearing temporally resolving detector, map transverse beam phase space distribution at exit. As result, proton bunch radius appears to grow along results divergence increase bunch, related with spatial growth self-modulated wakefields. In addition, asymmetric structures are result asymmetries divergence, and do not...
We use particle-in-cell (PIC) simulations to study the effects of variations incoming 400 GeV proton bunch parameters on amplitude and phase wakefields resulting from a seeded self-modulation (SSM) process. find that these are largest during growth SSM, i.e., over first five six meters plasma with an electron density $7\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$. However, for any single parameter by $\ifmmode\pm\else\textpm\fi{}5%$, after SSM...
In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from Super Proton Synchrotron (SPS) at CERN. The angular distribution protons deflected due to SSM is quantitative measure process, which agrees with simulations by two-dimensional (axisymmetric) particle-in-cell code LCODE. Agreement achieved for populations between $10^{11}$ and $3 \times 10^{11}$ particles, various plasma density gradients ($-20 \div 20\%$) two densities ($2\times 10^{14} \text{cm}^{-3}$...
A precise characterization of the incoming proton bunch parameters is required to accurately simulate self-modulation process in Advanced Wakefield Experiment (AWAKE). This paper presents an analysis bunches used later stages AWAKE Run 1 data-taking period. The transverse structure observed at multiple positions along beamline using scintillating or optical transition radiation screens. a model that describes dimensions and divergence are fitted represent data Bayesian inference. tested on...