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ABSTRACT: We investigate by particle-in-cell simulations in two and three dimensions the laser-plasma interaction and the proton acceleration in multilayer targets where a low-density ("near-critical") layer of a few-micron thickness is added on the illuminated side of a thin, high-density layer. This target design can be obtained by depositing a "foam" layer on a thin metallic foil. The presence of the near-critical plasma strongly increases both the conversion efficiency and the energy of electrons and leads to enhanced acceleration of protons from a rear side layer via the target normal sheath acceleration mechanism. The electrons of the foam are strongly accelerated in the forward direction and propagate on the rear side of the target, building up a high electric field with a relatively flat longitudinal profile. In these conditions the maximum proton energy is up to three times higher than in the case of the bare solid target.
Physical Review E 03/2012; 85(3 Pt 2):036405. · 2.26 Impact Factor
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M. Ferrario,
D. Alesini,
M. Anania,
A. Bacci,
M. Bellaveglia,
R. Boni,
M. Castellano,
E. Chiadroni,
A. Cianchi,
C. De Martinis, [......],
L. Giannessi,
A. Petralia,
M. Quattromini,
C. Ronsivalle,
I. Spassovsky,
V. Surrenti,
L. Gizzi,
L. Labate,
T. Levato,
J.V. Rau
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ABSTRACT: A new facility named SPARC_LAB has been recently launched at the INFN National Laboratories in Frascati, merging the potentialities of the former projects SPARC and PLASMONX. We describe in this paper the status and the future perspectives at the SPARC_LAB facility.
IPAC, New Orleans, USA; 01/2012
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P Valente,
F Anelli,
A Bacci,
D Batani,
M Bellaveglia,
R Benocci,
C Benedetti,
L Cacciotti,
C A Cecchetti,
A Clozza, [......],
V Lollo, P Londrillo,
S Martellotti,
E Pace,
N Pathak,
A Rossi,
F Tani,
L Serafini,
G Turchetti,
C Vaccarezza
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2011; 653(1):42-46. · 1.21 Impact Factor
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ABSTRACT: In this paper we will briefly introduce laser–plasma acceleration for electrons and present some numerical simulations. The simulations have been performed to find a suitable working point for one of the test experiments of the INFN–CNR PLASMONX project. FLAME (Frascati laser for acceleration and multidisciplinary experiments), a 300 TW Ti:Sa laser, is being installed and commissioned at Laboratori Nazionali di Frascati (LFN). The first pilot experiment SITE (self-injection test experiment) is planned for this year (2010). The simulations have been run using a fully self-consistent particle-in-cell code AlaDyn (Acceleration by LAser and DYNamics of charged particles) developed and maintained at the Department of Physics at the University of Bologna within the PLAMSONX project.
Radiation Effects & Defects in Solids: Incorporating Plasma Science & Plasma Technology. 06/2010; 165(6-10):803-808.
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R Faccini,
F. Anelli,
A Bacci,
D Batani,
M Bellaveglia,
R. Benocci,
C. Benedetti,
L. Cacciotti,
C A Cecchetti,
A. Clozza, [......], P. Londrillo,
S. Martellotti,
E. Pace,
N. Patack,
A Rossi,
F. Tani,
L. Serafini,
G. Turchetti,
C. Vaccarezza,
P. Valente
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ABSTRACT: The advance in laser plasma acceleration techniques pushes the regime of the resulting accelerated particles to higher energies and intensities. In particular the upcoming experiments with the FLAME laser at LNF will enter the GeV regime with almost 1pC of electrons. From the current status of understanding of the acceleration mechanism, relatively large angular and energy spreads are expected. There is therefore the need to develop a device capable to measure the energy of electrons over three orders of magnitude (few MeV to few GeV) under still unknown angular divergences. Within the PlasmonX experiment at LNF a spectrometer is being constructed to perform these measurements. It is made of an electro-magnet and a screen made of scintillating fibers for the measurement of the trajectories of the particles. The large range of operation, the huge number of particles and the need to focus the divergence present unprecedented challenges in the design and construction of such a device. We will present the design considerations for this spectrometer and the first results from a prototype. Comment: 7 pages, 6 figures, submitted to NIM A
02/2010;
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Il Nuovo Cimento C 02/2009; 32(2):261-266.
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Il Nuovo Cimento C. 01/2009; 32:109-113.
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ABSTRACT: In this paper, we present acceleration by laser and dynamics of charged particles (ALaDyn), a particle-in-cell code, to investigate the interaction of a laser pulse with a preformed plasma and/or an externally injected beam. The code, fully parallelized, works in 1D, 2D, and 3D Cartesian geometry, and it is based on compact high-order finite-difference schemes ensuring higher spectral accuracy. We discuss the features, the performances, and the validation tests of the code. We finally present a preliminary application on a physically relevant case based on the PLASMON-X experiment of the CNR-INFN.
IEEE Transactions on Plasma Science 09/2008; · 1.17 Impact Factor
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ABSTRACT: In this paper we examine some consequences of the inverse Compton effect in the radio galaxies due to the presence of a universal
black-body radiation at 3 °K. In particular it will be shown that the observed X-ray diffuse radiation between 1 keV-1 MeV
may be interpreted as inverse Compton radiation from the strong and extended radio galaxies if this class of sources evolve
withz and magnetic fields of a few µG are typically present. The Compton losses, and their relevance to the problem of the radio
source spectra, are discussed. It will be shown that, if the average magnetic field is within the range (1 ÷ 3) µG, then the
radio data point to an interpretation in which the expected breaks in the spectra occur at high frequencies. Then we estimate
that the particles must escape from the systems in a time of at least ∼3·106 years. It is also pointed out that at high red-shift the Compton losses become so strong, as to drastically reduce the lifetime
of the radio sources, so that important cosmological consequences may be expected.
In questo articolo vengono esaminate alcune conseguenze dell’interazione Compton inverso, nelle radio Galassie, dovuta alla
presenza di una radiazione universale di corpo nero a 3 °K. Si dimostra, in particolare, che la radiazionex diffusa, osservata tra 1 keV e 1 MeV può essere interpretata in termini di radiazione Compton prodotta nelle radio Galassie
forti ed estese, se tale classe di sorgenti evolve conz, e in esse sono presenti tipicamente campi magnetici di alcuni µG. Vengono inoltre discusse le perdite Compton in riferimento
al problema dello spettro delle radio sorgenti. Si dimostra come, se i campi magnetici medi si mantengono nell’intervallo
(1 ÷ 3) µG, sia possibile inferire dai dati radio che il l’interruzione nello spettro, previsto teoricamente, si trovi alle
alte frequenze. Si stima quindi un tempo medio di fuga delle particelle dal sistema di 3 · 106 anni almeno. Viene infine rilevato come ai forti spostamenti verso il rosso la dissipazione Compton divenga così forte da
ridurre drasticamente la vita media delle radio sorgenti, sicché importanti conseguenze cosmologiche possono derivarne.
В зтой статье мы исследуем некоторые следствия обратного зффекта Комптона в радио-галактиках, обусловленного наличием универсального
иэлучения черного тела при 3 °К. В частности, будет покаэано, что наблюдаемое диффуэное иэлучение рентгеновских лучей между
1 кзВ и 1 МзВ можно интерпретировать как обратное комптоновское иэлучение от мошных и растянутых радио-галактик, если зтот
класс источников раэвивается с z, и имеются магнитные поля в несколько цG. Обсуждаются комптоновские потери и их уместность
в проблеме спектров радио источников. Будет покаэано, что если среднее магнитное поле расположено в области (1÷3)µG, то радио
данные приводят к интерпретации, в которой ожидаемые нарущения спектров происходят при высоких частотах. Затем мы оцениваем,
что частицы должны убегать иэ систем эа время, по крайней мере, ∼3·106 лет. Также отмечается, что при больщом красном сдвиге
комптоновские потери становятся настолько интенсивными, что сушественно сокрашается время жиэни радио источников и что можно
ожидать важных космологических последствий.
Il Nuovo Cimento B 04/1967; 52(2):495-506.
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ABSTRACT: We present a numerical scheme to solve the fully 3D Maxwell–Vlasov equations. The aim is to investigate the interaction of a laser pulse with a plasma and the acceleration of electrons and ions. We choose the approach based on numerical particles to approximate the distribution function interpreted, according to the Klimontovich formalism, as a probability distribution function. The key points are a high order implicit scheme to approximate the space differential operators and a time evolution scheme of adequate accuracy.
Communications in Nonlinear Science and Numerical Simulation.
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ABSTRACT: We present some numerical studies and parameter scans performed with the electromagnetic, relativistic, fully self-consistent Particle-In-Cell (PIC) code ALaDyn (Acceleration by LAser and DYNamics of charged particles), concerning the generation of a low emittance, high charge and low momentum spread electron bunch from laser–plasma interaction in the Laser WakeField Acceleration (LWFA) regime, in view of achieving beam brightness of interest for FEL applications.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, v.606, 89-93 (2009).
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ABSTRACT: We show that with an eighth order scheme the dispersion relation is very accurately reproduced and the numerical Cherenkov effect is small so that a good isotropy is obtained for the phase velocity. The comparison with an exact solution for the Gaussian wave packet confirms the accuracy of the method. The evolution of particles in the plane wave field is considered and an analysis of the first integrals of motion confirm the accuracy of the characteristics of the distribution function.
Communications in Nonlinear Science and Numerical Simulation.
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ABSTRACT: We present a general framework to design Godunov-type schemes for multidimensional ideal magnetohydrodynamic (MHD) systems, having the divergence-free relation and the related properties of the magnetic field B as built-in conditions. Our approach mostly relies on the constrained transport (CT) discretization technique for the magnetic field components, originally developed for the linear induction equation, which assures and its preservation in time to within machine accuracy in a finite-volume setting. We show that the CT formalism, when fully exploited, can be used as a general guideline to design the reconstruction procedures of the vector field, to adapt standard upwind procedures for the momentum and energy equations, avoiding the onset of numerical monopoles of O(1) size, and to formulate approximate Riemann solvers for the induction equation. This general framework will be named here upwind constrained transport (UCT). To demonstrate the versatility of our method, we apply it to a variety of schemes, which are finally validated numerically and compared: a novel implementation for the MHD case of the second-order Roe-type positive scheme by Liu and Lax [J. Comput. Fluid Dyn. 5 (1996) 133], and both the second- and third-order versions of a central-type MHD scheme presented by Londrillo and Del Zanna [Astrophys. J. 530 (2000) 508], where the basic UCT strategies have been first outlined.
Journal of Computational Physics.
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[show abstract]
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ABSTRACT: We present a numerical scheme to solve the fully 3D Maxwell-Vlasov equations. The aim is to investigate the interaction of a laser pulse with a plasma and the acceleration of electrons and ions. We choose the approach based on numerical particles to approximate the distribution function interpreted, according to the Klimontovich formalism, as a probability distribution function. The key points are a high order implicit scheme to approximate the space dieren tial operators and a time evolution scheme of adequate accuracy.
