Download citation plasma beatwave acceleration among all the advanced accelerator concepts that use lasers as the power source, most of the effort to. We analytically study the generation of longitudinal plasma waves in an underdense plasma by two electromagnetic waves with frequency difference approximately equal to the plasma frequency, as envisioned in the plasma beatwave accelerator concept of tajima and dawson. Riding the wave to the next generation xray light sources. Pdf experimental study of the plasma beat wave accelerator. Recently, the free wave accelerator fwa was proposed whereby a large net energy is imparted to electrons via the field of an extremely powerful laser whose intensity produces quiver energies significantly greater than the electron rest mass. An overview is given of the physics issues relevant to the plasma wakefield accelerator, the plasma beatwave accelerator, the laser wakefield accelerator, including the selfmodulated regime, and wakefield accelerators driven by multiple electron or laser pulses. Robust autoresonant excitation in the plasma beatwave. Putting plasma to work diy fusion reactors, magnetrons and more. In this paper we describe the recent work at ucla on the acceleration of externally injected electrons by a relativistic plasma wave. Our present concern is the accelerator issues of plasma accelerators, which are discussed in section 4. Progress on laser plasma accelerators, proceedings of spie.
Since the plasma wave is not resonantly driven, as in the beatwave, the. Controlled injection and acceleration of electrons in. The physics of the beatexcited, relativistic electron plasma wave, a candidate for a laser particle accelerator, is studied in experiments at ucla. Overview of plasmabased accelerator concepts abstract. Ultrahighcharge electron beams from laserirradiated. The original plasma accelerator schemes investigated in the 1980s and 1990s were based on a longpulse laser.
A plasma is a quasineutral, electrically conductive fluid. Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons, and ions, using the electric field associated with electron plasma wave or other highgradient plasma structures like shock and sheath fields. Modulational instability of a plasma wave in a beatwave accelerator article pdf available in jetp letters 45 january 1987 with 3 reads how we measure reads. Review of plasma sources in the view of a beatwave accelerator experiment. A numerical model of the plasma beatwave accelerator.
A modified version of the plasma beatwave accelerator scheme is introduced and analyzed, which is based on autoresonant phaselocking of the nonlinear langmuir wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. Review of plasma sources in the view of a beatwave. Kiss makes editing wav files as easy as editing text with its clear user interface and powerful effects. In laserdriven plasmawave electron accelerators wim leemans and eric esarey wim leemansheads the loasis lasers, optical accelerator systems integrated studies program at the lawrence berkeley national laboratory in berkeley, california. Demonstration of plasma beat wave acceleration of electrons from 2. He is known for his pioneering work in plasmabased particle acceleration techniques for which he won the 2006 james clerk maxwell prize for plasma physics. A plasma beatwave accelerator is proposed to drive the plasma wave for ionization injection, where the beating of the lasers effectively produces a train of longwavelength pulses. The plasma wave in turn is produced by two colinear laser pulses whose amplitude is modulated so that the beat. We analytically study the generation of longitudinal plasma waves in an underdense plasma by two electromagnetic waves with frequency difference approximately equal to the plasma frequency, as envisioned in the plasma beat wave accelerator concept of tajima and dawson. Pdf acceleration of injected electrons by the plasma.
In the plasma beat wave accelerator, acceleration is achieved by a longitudinal electrostatic field produced as a result of charge separation generated by a plasma wave traveling close to the speed of light. Provided the plasma wave phase velocity remains equal to the beat wave phase velocity, then phase detuning between the accelerated electrons and the plasma wave is no longer a limiting factor in determining the maximum energy gain in the plasma heat wave accelerator. As the electron plasma waves maximum amplitude is immediately behind the pulse, it requires no growth phase as do other schemes such as the laser beat wave 3. We describe the results from recent experimental on the plasma beat wave accelerator pbwa scheme at ucla. Accelerator physics issues such as the luminosity are discussed. This new scheme is designed to overcome some of the wellknown limitations of previous approaches, namely relativistic. Twocolor ionization injection using a plasma beatwave. High energy laser plasma accelerators laser and particle. As the plasma wave grows to sufficiently large amplitudes, however, it. Basic concepts in plasma accelerators royal society publishing.
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. Alloptical control of nonlinear focusing of laser beams in plasma beat wave accelerator serguei y. We obtain analytic expressions for the plasma frequency, longitudinal electron velocity, plasma density and longitudinal plasma electric field of a nonlinear longitudinal electron plasma oscillation with amplitude less than the wavebreaking limit and phase velocity. Alloptical control of nonlinear focusing of laser beams in plasma beat wave accelerator serguei kalmykov, s austin yi and gennady shvets. Progress on laser plasma accelerators progress on laser plasma accelerators chen, pisin 19861021 00. In the simplest case, it is composed of electrons and a single species of positive ions, but it may also contain multiple ion species including negative ions as well as neutral particles.
The plasma acceleration structures are created either using ultrashort laser pulses or energetic particle beams that are matched to the plasma. Physics of laserdriven and beamdriven plasma accelerators. Abstract we analytically study the generation of longitudinal plasma waves in an underdense plasma by two electromagnetic waves with frequency difference approximately equal to the plasma frequency, as envisioned in the plasma beatwave accelerator concept of. We perform an analytic study of some quantities relevant to the plasma beatwave accelerator pbwa concept. We perform an analytic study of some quantities relevant to the plasma beat wave accelerator pbwa concept. Experimental results are compared with theoretical predictions, and future prospects for the plasma beat wave accelerator are discussed.
Optical guiding and beat wave phase velocity control in. He is currently distinguished professor of electrical engineering, the director of the center for. Laser plasma acceleration techniques have successfully been used either for acceleration of injected electrons or. Using the beat wave method, electric fields of 1 10 have been produced and electrons have been accelerated with an energy gain from 1 mev to more than 30 mev. The plasma wave in turn is produced by two colinear laser pulses whose amplitude is modulated so that the beat frequency matches the plasma frequency. Acceleration of injected electrons by the plasma beat wave. A minimalistic console interface is used to enter plot expressions in a syntax similar to. No accelerated lectrons above the detection threshold were observed when the laser was operated on a single frequency or when no electrons were injected. Theory indicates that a very high acceleration gradient, of order 1 gevm, can exist in the plasma wave driven by the beating lasers.
Riding the plasma wave of the future symmetry magazine. Plasma beat wave accelerator, acceleration is achieved by an electrostatic field produced as a result of charge separation generated by a plasma wave traveling close to the speed of light. Acceleration of injected electrons by the plasma beat wave accelerator. Preliminary experiments have shown waves excited up to % of the cold wavebreaking amplitude, corresponding to longitudinal electric fields of 0. Twocolor laser ionization injection is a method to generate ultralow emittance sub100 nm transverse normalized emittance beams in a laserdriven plasma accelerator. Our wave form editing window allows you to find the part you want to edit quickly. Citeseerx document details isaac councill, lee giles, pradeep teregowda. A modified version of the plasma beatwave accelerator scheme is presented, which is based on autoresonant phaselocking of the nonlinear langmuir wave to the slowly chirped beat frequency of the. Plasma is an open source plotter that plots functions, vector fields, and parametric curves in 2d and 3d. Alloptical control of nonlinear focusing of laser beams. In the plasma beat wave accelerator, acceleration is achieved by an electrostatic field produced as a result of charge separation generated by a plasma wave traveling close to speed of light. Using a plasma beatwave accelerator for wakefield excitation, compared to short. A creative group of trailblazers is reinventing particle acceleration by making electrons and positrons surf a wave of plasma.
This new scheme is designed to overcome some of the wellknown limitations of previous approaches, namely relativistic detuning. The relativistic electron fluid equa tions describing driven electron oscillations with phase velocities near the speed of light in a cold, collisionless plasma are reduced to a single, approximate ordinary. Shortpulse lasers did not exist because chirped pulse amplication had not yet been demonstrated in the optical regime, only in the microwave regime. Plasma electron selftrapping threshold increases as plasma wave phase velocity increases. The plasma beat wave accelerator pbwalj2 employs two laser beams beating at the plasma frequency to drive the plasma while the plasma. Issues addressed here include possible experimental limitations on the length, growth. This new scheme is designed to overcome some of the wellknown limitations of previous approaches, namely. In plasma physics, waves in plasmas are an interconnected set of particles and fields which propagate in a periodically repeating fashion. For short laser pulses, this is the laser wakefield accelerator lwfa concept. Some preliminary experiments have shown that electrons can be accelerated in plasma waves generated by the wakefield method. At the first stage, the main attention was attracted to plasma beat wave accelerator scheme pbwa where twofrequency laser radiation was used to create a plasma wave. Twocolor ionization injection using a plasma beatwave accelerator. We report an experimental study of the beatwave excitation of plasma waves using a short pulse, high intensity co2 laser with two colinearly propagating beams to excite the fast wave vp c in a longscalelength underdense plasma.
The concepts of laserplasma based accelerator and injector are discussed here. A two frequency laser was used to excite a plasma wave over a narrow range of static gas pressures close to resonance. Note that these laser parameters are achievable at present co 2 laser facilities 28, 29. Computer physics communications computer physics communications 69 1992 29905 northholland a numerical model of the plasma beatwave accelerator paul gibbon 1 maxplanckinstitut f biophysikalische chemie, abteilung laserphysik, w3400 gottingennikolausberg, germany received 1 february 1991. Electrons with energies up to our detection limit of 9. Experimental study of the plasma beat wave accelerator.
Plasma based chargedparticle accelerators iopscience. Advanced accelerator concepts to overcome some of these problems are proposed, including various forms of the plasma fiber accelerator. An advanced laser architecture suitable for the beatwave accelerator is suggested. Overview of plasmabased accelerator concepts eric esarey, phillip sprangle, senior member, ieee, jonathan krall, and antonio ting invited abstractan overview is given of the physics issues relevant to the plasma wakefield accelerator, the plasma beatwave accelera tor, the laser wakefield accelerator, including the selfmodulated. In laserplasma based particle accelerators, a second laser pulse colliding with the first is used to obtain better control over the injection and subsequent acceleration of electrons.
In studies of laserplasma acceleration lpa, several laser wakefield accelerator lwfa concepts have been proposed in the last few decades, including the plasma beat wave accelerator 1, 2, the selfmodulated laser wakefield accelerator smlwfa, the crossmodulated laser wakefield accelerator xmlwfa, and lwfa in the bubble regime. Electron acceleration by means of short powerful laser. Plasma wakefield accelerators can subvert this problem by filling the accelerator cavity with plasma a soup of ionized gas in which electrons are stripped from. The plasma beatwave accelerator excites a large amplitude plasma wave with low peak laser electric fields, leaving atomicallybound electrons with low ionization. Citeseerx the plasma beat wave accelerator i experiments.
As the laser pulse moves through the plasma at group velocity vg c, the oscillating electrons show up macroscopically as a plasma mode or wave with frequency w equal to the plasma frequency and k wvg. Controlled studies of wavewave interactions in a beat. Plasma beatwave acceleratorinis international nuclear iaea. In this paper we report on experiments designed to study basic physics issues which are of importance to schemes which are currently under study at ucla and elsewhere. The process of driving a plasma with a laser pump containing two frequencies has enjoyed renewed interest in the past several years due to interest in the plasma beatwave accelerator pbwa scheme 1. Chandrashekhar chan janardan joshi born july 22, 1953, at wai, maharashtra, india is an indianamerican experimental plasma physicist.
These methods have ranged from various kinds of plasma wave accelerators to inverse free electron lasers. Diffraction of the leading part of the laser pulse ruins the synchronism between the plasma wave and. With development of chirped pulse amplification cpa and powerful. Pdf modulational instability of a plasma wave in a beat. The plasma wave in turn is pro duced by colinear two laser pulses whose amplitude is modulated so that. The physics of the beat excited, relativistic electron plasma wave, a candidate for a laser particle accelerator, is studied in experiments at ucla.
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