The Ultralac : A Collective Wave Accelerator for Ultrarelativistic Particles (original) (raw)
Related papers
Cornell University - arXiv, 2022
In an electron wakefield accelerator, an intense laser pulse or charged particle beam excites plasma waves. Under proper conditions, electrons from the background plasma are trapped in the plasma wave and accelerated to ultra-relativistic velocities. We present recent results from a proof-of-principle wakefield acceleration experiment that reveal a unique synergy between a laser-driven and particle-driven accelerator: a high-charge laser-wakefield accelerated electron bunch can drive its own wakefield while simultaneously drawing energy from the laser pulse via direct laser acceleration. This continues to accelerate electrons beyond the usual decelerating phase of the wakefield, thus reaching much higher energies. Here, we inject several nanocoulombs of electrons into a petawatt-laser-driven plasma wake using pre-distributed ionized aluminium nanoparticles. The laser pulse duration (135±10 fs) and high energy (130±10 J) enable the laser pulse to fulfill multiple roles: the leading edge ionizes the helium gas and nanoparticles, the main part drives a nonlinear plasma wave, and the trailing part replenishes electron energy through direct laser acceleration mechanism. We find that the 10-centimetre-long accelerator can generate 340 pC, 10.4±0.2 GeV electron bunches with 3.4 GeV RMS energy spread and 0.9 mrad RMS divergence. It can also produce bunches with lower energy, a few percent energy spread, and higher charge. This synergistic mechanism and the simplicity of the experimental setup represent a significant step towards compact tabletop particle accelerators suitable for driving x-ray free-electron lasers and novel types of radiation sources producing muon and positron beams.
Design and validation of an accelerator for an ultracold electron source
Physical Review Special Topics - Accelerators and Beams, 2008
We describe here a specially designed accelerator structure and a pulsed power supply that are essential parts of a high brightness cold atoms-based electron source. The accelerator structure allows a magnetooptical atom trap to be operated inside of it, and also transmits subnanosecond electric field pulses. The power supply produces high voltage pulses up to 30 kV, with a rise time of up to 30 ns. The resulting electric field inside the structure is characterized with an electro-optic measurement and with an ion timeof-flight experiment. Simulations predict that 100 fC electron bunches, generated from trapped atoms inside the structure, reach an emittance of 0.04 mm mrad and a bunch length of 80 ps.
Ultrashort-pulse relativistic electron gun/accelerator
Laser driven plasma waves have up to now been considered exclusively as second stage accelerators. Conventional finacs are used in this case as the first stage of acceleration to inject MeV electrons into the plasma. This paper shows it to be advantageous to instead use laser wake fields in the first stage for greater simplicity and better emittance. The concept presented makes this possible with all-optical generation and acceleration of electrons. It is tested using two dimensional particle-in-cell simulations.
A short-pulse electron linear accelerator for laser driven particle acceleration research
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
Critical aspects of high-gradient electron acceleration by laser-driven relativistic electron plasma waves have been studied experimentally. A number of important features incorporated into the design of the experimental facility make it possible to obtain controlled injection of high-energy electrons into the plasma and make reliable measurements of electron acceleration. Effective accelerating electric field gradients of approximately 1.7 GeVim have been obtained in centimeter-length plasmas.
Plasma based charged-particle accelerators
Plasma Physics and Controlled Fusion, 2004
Studies of charged-particle acceleration processes remain one of the most important areas of research in laboratory, space and astrophysical plasmas. In this paper, we present the underlying physics and the present status of high gradient and high energy plasma accelerators. We will focus on the acceleration of charged particles to relativistic energies by plasma waves that are created by intense laser and particle beams. The generation of relativistic plasma waves by intense lasers or electron beams in plasmas is important in the quest for producing ultra-high acceleration gradients for accelerators. With the development of compact short pulse high brightness lasers and electron positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultrahigh acceleration gradients. These include the plasma beat wave accelerator mechanism, which uses conventional long pulse (∼100 ps) modest intensity lasers (I ∼ 10 14-10 16 W cm −2), the laser wakefield accelerator (LWFA), which uses the new breed of compact high brightness lasers (<1 ps) and intensities >10 18 W cm −2 , the self-modulated LWFA concept, which combines elements of stimulated Raman forward scattering, and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomena such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm −1 have been generated with particles being accelerated to 200 MeV over a distance of millimetre. Plasma wakefields driven by positron beams at the Stanford Linear Accelerator Center facility have accelerated the tail of the positron beam. In the near future, laser plasma accelerators will be producing GeV particles.
Electron surfing acceleration by mildly relativistic beams: wave magnetic field effects
New Journal of Physics, 2008
Electron surfing acceleration (ESA) is based on the trapping of electrons by a wave and the transport of the trapped electrons across a perpendicular magnetic field. ESA can accelerate electrons to relativistic speeds and it may thus produce hot electrons in plasmas supporting fast ion beams, like close to astrophysical shocks. One-dimensional (1D) particle-in-cell (PIC) simulations have demonstrated that trapped electron structures (phase space holes) are stabilized by relativistic phase speeds of the waves, by which ESA can accelerate electrons to ultrarelativistic speeds. The 2(1/2)D electromagnetic and relativistic PIC simulations performed in the present paper model proton beam driven instabilities in the presence of a magnetic field perpendicular to the simulation plane. This configuration represents the partially electromagnetic mixed modes and the filamentation modes, in addition to the Buneman waves. The waves are found to become predominantly electromagnetic and nonplanar for beam speeds that would result in stable trapped electron structures. The relativistic boost of ESA reported previously is cancelled by this effect. For proton beam speeds of 0.6 and 0.8c, the electrons reach only million electron volt energies. The system with the slower beam is followed sufficiently long in time to reveal the development of a secondary filamentation instability. The instability forms a channel in the simulation domain that is void of any magnetic field. Proton beams may thereby cross perpendicular magnetic fields for distances beyond their gyroradius.
Particle beams in ultrastrong laser fields: direct laser acceleration and radiation reaction effects
Journal of Physics: Conference Series, 2015
Several aspects of the interaction of particle beams with ultrastrong laser fields are discussed. Firstly, we consider regimes when radiation reaction is not essential and it is demonstrated that employing chirped laser pulses, significant improvement of the direct acceleration of particles can be achieved. Results from single-and many-particle calculations of the particle acceleration, in vacuum, by plane-wave fields, as well as in tightly-focused laser beams, show that the mean energies and their spreads qualify them for important applications. Secondly, we investigate the effect of radiation reaction in electron-laser-beam interactions. Signatures of the quantum radiation reaction during the interaction of an electron bunch with a focused superstrong ultrashort laser pulse can be observed in a characteristic behavior of the spectral bandwidth, and the angular spread of the nonlinear Compton radiation on the laser pulse duration. Furthermore, it is shown that the radiation reaction effects can be employed to control the electron dynamics via the nonlinear interplay between the Lorentz and radiation reaction forces. In particular, it is shown that an ultrarelativistic electron bunch colliding headon with a strong bichromatic laser pulse can be deflected in a controllable way, by changing either the relative phase or the relative amplitude between the two frequency components of the bichromatic field.
Laser Wakefield Acceleration : An Advanced Technique for Compact Electron Accelerators
2013
High energy particle (electron/proton/ion) accelerators are required for addressing various fundamental questions e.g. particle physics research, search for new particles, origin of mass, identity of dark matter, extra dimension of space, and many other applications. During last 50 years or so, many high energy particle accelerators have been built worldwide for exploring above mentioned fundamental scientific issues, and have led to many important scientific discoveries. These accelerators have been built using radio-frequency (RF) based acceleration technique where the acceleration gradient is limited to <100 MV/m,due to the material breakdown on the walls of the RF accelerating cavities. Therefore, such accelerators are quite big in size e.g. Stanford Linear Accelerator (SLAC), USAand Large Hadron Collider (LHC), CERN, Geneva. The quest for higher and higher energy of the particles to go deeper into the fundamental questions is driving the scientific community to build even bi...