John Farmer
A5034574812- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Laser-Plasma Interactions and Diagnostics
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Laser-Matter Interactions and Applications
- Magnetic confinement fusion research
- Particle physics theoretical and experimental studies
- Laser-induced spectroscopy and plasma
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Ionosphere and magnetosphere dynamics
- Spectroscopy Techniques in Biomedical and Chemical Research
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Pulsed Power Technology Applications
- Ion-surface interactions and analysis
- Astronomy and Astrophysical Research
- Plasma Diagnostics and Applications
- Atmospheric and Environmental Gas Dynamics
Max Planck Institute for Physics
2020-2025
University of Chicago
2016-2024
Scottish Universities Physics Alliance
2010-2024
University of Strathclyde
2009-2024
European Organization for Nuclear Research
2016-2024
Fermi National Accelerator Laboratory
2018-2024
Cockcroft Institute
2024
Sci-Tech Daresbury
2024
Institute of Astronomy and Space Physics
2021-2023
Consejo Nacional de Investigaciones Científicas y Técnicas
2021-2023
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...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment CERN the world׳s first experiment. AWAKE will be installed in former CNGS facility uses 400 GeV/c beam bunches from SPS. experiments focus on self-modulation instability of long (rms ~12 cm) bunch plasma. These are planned for end 2016. Later, 2017/2018, low energy (~15 MeV)...
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,...
Raman amplification in plasma has been proposed to be a promising method of amplifying short radiation pulses. Here, we investigate chirped pulse (CPRA) where the pump is and leads spatiotemporal distributed gain, which exhibits superradiant scaling linear regime, usually associated with nonlinear depletion Compton regimes. CPRA potential serve as high-efficiency high-fidelity amplifier/compressor stage.
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...
Plasma wakefields offer high acceleration gradients, orders of magnitude larger than conventional RF accelerators. However, the achievable luminosity remains relatively low, typically limited by repetition rate and charge accelerated per shot. In this work, we show that a train drive bunches can be harnessed to accelerate multiple witness in single We demonstrate periodically loading removes limit on energy transfer from beam plasma, which allows increased. Proof-of-concept simulations for...
In this paper we review the physics opportunities at linear $e^+e^-$ colliders with a special focus on high centre-of-mass energies and beam polarisation, take fresh look various accelerator technologies available or under development and, for first time, discuss how facility equipped technology mature today could be upgraded of tomorrow to reach much higher and/or luminosities. addition, will detectors alternative collider modes, as well beyond-collider experiments R\&D facilities part...
Abstract Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits conventional laser media. Here we show 1–100 J pump pulses can amplify picojoule seed nearly joule level. The extremely high gain also leads significant backscattered radiation “noise”, stochastic fluctuations competes with externally injected pulses, which are amplified similar levels at highest energies. energy is scattered into an...
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...
Abstract Stimulated Raman backscattering in plasma is potentially an efficient method of amplifying laser pulses to reach exawatt powers because fully broken down and withstands extremely high electric fields. Plasma also has unique nonlinear optical properties that allow simultaneous compression ultra-short durations. However, current measured efficiencies are limited several percent. Here we investigate amplification short duration seed with different chirp rates using a chirped pump pulse...
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...
Electron acceleration by laser-plasma techniques is approaching maturity and getting ready for the construction of particle accelerators with dedicated applications. We present a general methodology showing how beam physics studies can be used to achieve specific parameter set in accelerator. Laser systems, plasma targets, magnetic component properties are designed optimize electron so as required performances. Beam its full 6D phase space studied from injection delivery end user, through...
Abstract A Higgs Factory is considered the highest priority next collider project by high-energy physics community. Very advanced designs based on radio-frequency cavities exist, and variations this approach are still being developed. Recently, an option electron-bunch driven plasma wakefield acceleration has also been proposed. In article, we discuss a further proton-driven acceleration. This significant potential advantages due to high energy of driver, simplifying stage. Its success will...
We use a combination of spatial distribution and radial velocity to search for halo sub-structures in sample 412 RR Lyrae stars (RRLS) that covers $\sim 525$ square degrees region the Virgo Overdensity (VOD) spans distances from Sun 4 75 kpc. With friends-of-friends algorithm we identified six high significance groups RRLS phase space, which associate mainly with VOD Sagittarius stream. Four other were also flagged as less significant overdensities. Three 3 lower have between 10$ 20 kpc,...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation J. P. Farmer, B. Ersfeld, D. A. Jaroszynski; Raman amplification in plasma: Wavebreaking heating effects. Phys. Plasmas 1 November 2010; 17 (11): 113301. https://doi.org/10.1063/1.3492713 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar...
The attainable transformer ratio in plasma accelerators is limited by instabilities. Using three-dimensional particle-in-cell simulations, we demonstrate that these can be controlled using a hollow channel with co-axial filament. driver scatters electrons from the filament, and slow pinch of ions leads to strong chirp effective betatron frequency, preventing beam breakup. We monoenergetic acceleration an electron bunch 20 GeV over 4.4 m, achieving 10, energy efficiency 40% emittance 1.8 um.
Abstract Following the successful Run 1 experiment, Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) Run2 experiment requires design and implementation of a compact electron source. The “high-quality Electron Accelerator driven by Reliable Laser wakefield for Industrial uses” (EARLI) project aims to stand-alone high-quality injector based on laser accelerator (LWFA) as an alternative proposal AWAKE’s baseline X-band gun. This is currently in phase, including...
We present a laser-assisted electron injection scheme for beam-driven plasma wakefield acceleration. The laser is collinear with the driver and triggers of hot electrons into wake by interaction thin solid target. baseline case using AWAKE Run 2 parameters then perform variations on key to explore scheme. It found that trapped witness charge may be tuned altering parameters, strong dependence phase upon injection. Normalized emittance settles at order micrometres varies charge. robust...