N. Torrado
A5050943956- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Ion-surface interactions and analysis
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Atomic and Molecular Physics
- Electrostatic Discharge in Electronics
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
University of Lisbon
2021-2025
European Organization for Nuclear Research
2023-2024
Campbell Collaboration
2022-2023
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...
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,...
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...
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...
High-voltage pulsed gas discharges can produce suitable plasma for wakefield particle acceleration experiments. Such plasmas are challenging loads characterized by significant parasitic elements and fast impedance transitions leading to hard-to-predict dynamic behavior. This hinders the use of solid-state pulse generators replace inefficient limited lifetime spark gaps or thyratrons. article presents development, simulation, test a new semiconductor-based double generator 5-m-long load. It...
We show experimentally that an effect of motion ions, observed in a plasma-based accelerator, depends inversely on the plasma ion mass. The appears within single wakefield event and manifests itself as bunch tail, occurring only when sufficient ions suppresses wakefields. Wakefields are driven resonantly by multiple bunches, simulation results indicate ponderomotive force causes ions. In this case, is also expected to depend amplitude wakefields, confirmed through variations drive charge.
We observe for the first time an effect on driver caused by motion of ions in a plasma wakefield accelerator. The manifests itself as beam tail, which only occurs when sufficient suppresses wakefields. By changing (helium, argon, xenon) experiment, we show that depends inversely ion mass, predicted from theory and simulations. Wakefields are driven resonantly multiple bunches, simulation results indicate ponderomotive force causes ions. In this case, is also expected to depend amplitude...
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...
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...
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...
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, 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, confirming...
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. 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. The 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...