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Jiang K, Huang TW, Li R, Yu MY, Zhuo HB, Wu SZ, Zhou CT, Ruan SC. Branching of High-Current Relativistic Electron Beam in Porous Materials. PHYSICAL REVIEW LETTERS 2023; 130:185001. [PMID: 37204906 DOI: 10.1103/physrevlett.130.185001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/27/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023]
Abstract
Propagation of high-current relativistic electron beam (REB) in plasma is relevant to many high-energy astrophysical phenomena as well as applications based on high-intensity lasers and charged-particle beams. Here, we report a new regime of beam-plasma interaction arising from REB propagation in medium with fine structures. In this regime, the REB cascades into thin branches with local density a hundred times the initial value and deposits its energy 2 orders of magnitude more efficiently than that in homogeneous plasma, where REB branching does not occur, of similar average density. Such beam branching can be attributed to successive weak scatterings of the beam electrons by the unevenly distributed magnetic fields induced by the local return currents in the skeletons of the porous medium. Results from a model for the excitation conditions and location of the first branching point with respect to the medium and beam parameters agree well with that from pore-resolved particle-in-cell simulations.
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Affiliation(s)
- K Jiang
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
- College of Applied Sciences, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - T W Huang
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - R Li
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - M Y Yu
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - H B Zhuo
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - S Z Wu
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - C T Zhou
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
- College of Applied Sciences, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - S C Ruan
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
- College of Applied Sciences, Shenzhen University, Shenzhen 518060, People's Republic of China
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2
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Li R, Huang TW, Ju LB, Yu MY, Zhang H, Wu SZ, Zhuo HB, Zhou CT, Ruan SC. Nanoscale Electrostatic Modulation of Mega-Ampere Electron Current in Solid-Density Plasmas. PHYSICAL REVIEW LETTERS 2021; 127:245002. [PMID: 34951809 DOI: 10.1103/physrevlett.127.245002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 06/07/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Transport of high-current relativistic electron beams in dense plasmas is of interest in many areas of research. However, so far the mechanism of such beam-plasma interaction is still not well understood due to the appearance of small time- and space-scale effects. Here we identify a new regime of electron beam transport in solid-density plasma, where kinetic effects that develop on small time and space scales play a dominant role. Our three-dimensional particle-in-cell simulations show that in this regime the electron beam can evolve into layered short microelectron bunches when collisions are relatively weak. The phenomenon is attributed to a secondary instability, on the space- and timescales of the electron skin depth (tens of nanometers) and few femtoseconds of strong electrostatic modulation of the microelectron current filaments formed by Weibel-like instability of the original electron beam. Analytical analysis on the amplitude, scale length, and excitation condition of the self-generated electrostatic fields is clearly validated by the simulations.
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Affiliation(s)
- R Li
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - T W Huang
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - L B Ju
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - M Y Yu
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - H Zhang
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - S Z Wu
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - H B Zhuo
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - C T Zhou
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - S C Ruan
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
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Dover NP, Nishiuchi M, Sakaki H, Kondo K, Alkhimova MA, Faenov AY, Hata M, Iwata N, Kiriyama H, Koga JK, Miyahara T, Pikuz TA, Pirozhkov AS, Sagisaka A, Sentoku Y, Watanabe Y, Kando M, Kondo K. Effect of Small Focus on Electron Heating and Proton Acceleration in Ultrarelativistic Laser-Solid Interactions. PHYSICAL REVIEW LETTERS 2020; 124:084802. [PMID: 32167312 DOI: 10.1103/physrevlett.124.084802] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Acceleration of particles from the interaction of ultraintense laser pulses up to 5×10^{21} W cm^{-2} with thin foils is investigated experimentally. The electron beam parameters varied with decreasing spot size, not just laser intensity, resulting in reduced temperatures and divergence. In particular, the temperature saturated due to insufficient acceleration length in the tightly focused spot. These dependencies affected the sheath-accelerated protons, which showed poorer spot-size scaling than widely used scaling laws. It is therefore shown that maximizing laser intensity by using very small foci has reducing returns for some applications.
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Affiliation(s)
- N P Dover
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - M Nishiuchi
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - H Sakaki
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - Ko Kondo
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - M A Alkhimova
- Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russia
| | - A Ya Faenov
- Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russia
- Open and Transdisciplinary Research Initiative, Osaka University, Suita, Osaka 565-0871, Japan
| | - M Hata
- Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - N Iwata
- Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - H Kiriyama
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - J K Koga
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - T Miyahara
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - T A Pikuz
- Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russia
- Open and Transdisciplinary Research Initiative, Osaka University, Suita, Osaka 565-0871, Japan
| | - A S Pirozhkov
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - A Sagisaka
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - Y Sentoku
- Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Y Watanabe
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - M Kando
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - K Kondo
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
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Romagnani L, Robinson APL, Clarke RJ, Doria D, Lancia L, Nazarov W, Notley MM, Pipahl A, Quinn K, Ramakrishna B, Wilson PA, Fuchs J, Willi O, Borghesi M. Dynamics of the Electromagnetic Fields Induced by Fast Electron Propagation in Near-Solid-Density Media. PHYSICAL REVIEW LETTERS 2019; 122:025001. [PMID: 30720299 DOI: 10.1103/physrevlett.122.025001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 10/01/2018] [Indexed: 06/09/2023]
Abstract
The propagation of fast electron currents in near solid-density media was investigated via proton probing. Fast currents were generated inside dielectric foams via irradiation with a short (∼0.6 ps) laser pulse focused at relativistic intensities (Iλ^{2}∼4×10^{19} W cm^{-2} μm^{2}). Proton probing provided a spatially and temporally resolved characterization of the evolution of the electromagnetic fields and of the associated net currents directly inside the target. The progressive growth of beam filamentation was temporally resolved and information on the divergence of the fast electron beam was obtained. Hybrid simulations of electron propagation in dense media indicate that resistive effects provide a major contribution to field generation and explain well the topology, magnitude, and temporal growth of the fields observed in the experiment. Estimations of the growth rates for different types of instabilities pinpoints the resistive instability as the most likely dominant mechanism of beam filamentation.
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Affiliation(s)
- L Romagnani
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - A P L Robinson
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - R J Clarke
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - D Doria
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
- Extreme Light Infrastructure-Nuclear Physics (ELI-NP), Horia Hulubei Institute for Nuclear Physics (IFIN-HH), Reactorului Str., 30, Magurele 077126, Bucharest, Romania
| | - L Lancia
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - W Nazarov
- School of Chemistry, University of St. Andrews, St Andrews KY16 9ST, United Kingdom
| | - M M Notley
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - A Pipahl
- Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, 40225, Germany
| | - K Quinn
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - B Ramakrishna
- Department of Physics, Indian Institute of Technology Hyderabad 502285, India
| | - P A Wilson
- School of Engineering, University of South Australia, Adelaide SA 5095, Australia
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide SA 5000, Australia
| | - J Fuchs
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - O Willi
- Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, 40225, Germany
| | - M Borghesi
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
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5
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Shaikh M, Lad AD, Sarkar D, Jana K, Kumar GR, Rajeev PP. Measuring the lifetime of intense-laser generated relativistic electrons in solids via gating their Cherenkov emission. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013301. [PMID: 30709173 DOI: 10.1063/1.5054785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
Optical Kerr gating technique has been employed to investigate the life history of relativistic electrons in solids by temporally gating their Cherenkov emission. Mega-ampere currents of relativistic electrons are created during ultra-intense (2 × 1019 W/cm2) laser-solid interactions. In order to measure the lifetime of these relativistic electrons in solids, we temporally gate their Cherenkov emission using an optical Kerr gate (OKG). The OKG is induced in a nonlinear medium, namely, carbon-di-sulphide (CS2), with a measured gate-width (FWHM) of 2 ps. The gate femtosecond laser pulse is synchronized with the intense interaction pulse generating relativistic electrons. The arrival time of the gate laser pulse on the CS2 cell is varied with the help of a delay stage. We find that Cherenkov emission from relativistic electrons created with a ultra-short laser pulse (25 fs) lives as long as 120 ps, a few thousand times that of the incident light pulse.
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Affiliation(s)
- Moniruzzaman Shaikh
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Amit D Lad
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Deep Sarkar
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Kamalesh Jana
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - G Ravindra Kumar
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - P P Rajeev
- Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire QX11 0QX, United Kingdom
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6
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Shaikh M, Lad AD, Birindelli G, Pepitone K, Jha J, Sarkar D, Tata S, Chatterjee G, Dey I, Jana K, Singh PK, Tikhonchuk VT, Rajeev PP, Kumar GR. Mapping the Damping Dynamics of Mega-Ampere Electron Pulses Inside a Solid. PHYSICAL REVIEW LETTERS 2018; 120:065001. [PMID: 29481271 DOI: 10.1103/physrevlett.120.065001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/20/2017] [Indexed: 06/08/2023]
Abstract
We report the lifetime of intense-laser (2×10^{19} W/cm^{2}) generated relativistic electron pulses in solids by measuring the time evolution of their Cherenkov emission. Using a picosecond resolution optical Kerr gating technique, we demonstrate that the electrons remain relativistic as long as 50 picoseconds-more than 1000 times longer than the incident light pulse. Numerical simulations of the propagation of relativistic electrons and the emitted Cherenkov radiation with Monte Carlo geant4 package reproduce the striking experimental findings.
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Affiliation(s)
- Moniruzzaman Shaikh
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Amit D Lad
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Gabriele Birindelli
- Centre Lasers Intenses et Applications, University of Bordeaux-CNRS-CEA, Talence 33405, France
| | | | - Jagannath Jha
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Deep Sarkar
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Sheroy Tata
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Gourab Chatterjee
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Indranuj Dey
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Kamalesh Jana
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Prashant K Singh
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Vladimir T Tikhonchuk
- Centre Lasers Intenses et Applications, University of Bordeaux-CNRS-CEA, Talence 33405, France
| | - P P Rajeev
- Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire QX11 0QX, United Kingdom
| | - G Ravindra Kumar
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
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7
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Micron-scale mapping of megagauss magnetic fields using optical polarimetry to probe hot electron transport in petawatt-class laser-solid interactions. Sci Rep 2017; 7:8347. [PMID: 28827645 PMCID: PMC5566325 DOI: 10.1038/s41598-017-08619-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 07/17/2017] [Indexed: 11/10/2022] Open
Abstract
The transport of hot, relativistic electrons produced by the interaction of an intense petawatt laser pulse with a solid has garnered interest due to its potential application in the development of innovative x-ray sources and ion-acceleration schemes. We report on spatially and temporally resolved measurements of megagauss magnetic fields at the rear of a 50-μm thick plastic target, irradiated by a multi-picosecond petawatt laser pulse at an incident intensity of ~1020 W/cm2. The pump-probe polarimetric measurements with micron-scale spatial resolution reveal the dynamics of the magnetic fields generated by the hot electron distribution at the target rear. An annular magnetic field profile was observed ~5 ps after the interaction, indicating a relatively smooth hot electron distribution at the rear-side of the plastic target. This is contrary to previous time-integrated measurements, which infer that such targets will produce highly structured hot electron transport. We measured large-scale filamentation of the hot electron distribution at the target rear only at later time-scales of ~10 ps, resulting in a commensurate large-scale filamentation of the magnetic field profile. Three-dimensional hybrid simulations corroborate our experimental observations and demonstrate a beam-like hot electron transport at initial time-scales that may be attributed to the local resistivity profile at the target rear.
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8
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Göde S, Rödel C, Zeil K, Mishra R, Gauthier M, Brack FE, Kluge T, MacDonald MJ, Metzkes J, Obst L, Rehwald M, Ruyer C, Schlenvoigt HP, Schumaker W, Sommer P, Cowan TE, Schramm U, Glenzer S, Fiuza F. Relativistic Electron Streaming Instabilities Modulate Proton Beams Accelerated in Laser-Plasma Interactions. PHYSICAL REVIEW LETTERS 2017; 118:194801. [PMID: 28548516 DOI: 10.1103/physrevlett.118.194801] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Indexed: 06/07/2023]
Abstract
We report experimental evidence that multi-MeV protons accelerated in relativistic laser-plasma interactions are modulated by strong filamentary electromagnetic fields. Modulations are observed when a preplasma is developed on the rear side of a μm-scale solid-density hydrogen target. Under such conditions, electromagnetic fields are amplified by the relativistic electron Weibel instability and are maximized at the critical density region of the target. The analysis of the spatial profile of the protons indicates the generation of B>10 MG and E>0.1 MV/μm fields with a μm-scale wavelength. These results are in good agreement with three-dimensional particle-in-cell simulations and analytical estimates, which further confirm that this process is dominant for different target materials provided that a preplasma is formed on the rear side with scale length ≳0.13λ_{0}sqrt[a_{0}]. These findings impose important constraints on the preplasma levels required for high-quality proton acceleration for multipurpose applications.
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Affiliation(s)
- S Göde
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - C Rödel
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - K Zeil
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - R Mishra
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Gauthier
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F-E Brack
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - T Kluge
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - M J MacDonald
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- University of Michigan, Ann Arbor, Michigan 48109, USA
| | - J Metzkes
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - L Obst
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - M Rehwald
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - C Ruyer
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - H-P Schlenvoigt
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - W Schumaker
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - P Sommer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - T E Cowan
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - U Schramm
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, 01328 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - S Glenzer
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F Fiuza
- High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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9
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Dey I, Adak A, Singh PK, Shaikh M, Chatterjee G, Sarkar D, Lad AD, Kumar GR. Intense femtosecond laser driven collimated fast electron transport in a dielectric medium-role of intensity contrast. OPTICS EXPRESS 2016; 24:28419-28432. [PMID: 27958487 DOI: 10.1364/oe.24.028419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ultra-high intensity (> 1018 W/cm2), femtosecond (~30 fs) laser induced fast electron transport in a transparent dielectric has been studied for two laser systems having three orders of magnitude different peak to pedestal intensity contrast, using ultrafast time-resolved shadowgraphy. Use of a 400 nm femtosecond pulse as a probe enables the exclusive visualization of the dynamics of highest density electrons (> 7 × 1021 cm-3) observed so far. High picosecond contrast (~109) results in greater coupling of peak laser energy to the plasma electrons, enabling long (~1 mm), collimated (divergence angle ~2°) transport of fast electrons inside the dielectric medium at relativistic speeds (~0.66c). In comparison, the laser system with a contrast of ~106 has a large pre-plasma, limiting the coupling of laser energy to the solid and yielding limited fast electron injection into the dielectric. In the lower contrast case, bulk of the electrons expand as a cloud inside the medium with an order of magnitude lower speed than that of the fast electrons obtained with the high contrast laser. The expansion speed of the plasma towards vacuum is similar for the two contrasts.
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10
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Cristoforetti G, Anania MP, Faenov AY, Giulietti A, Giulietti D, Hansen SB, Koester P, Labate L, Levato T, Pikuz TA, Gizzi LA. Spatially resolved analysis of Kα x-ray emission from plasmas induced by a femtosecond weakly relativistic laser pulse at various polarizations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:023103. [PMID: 23496627 DOI: 10.1103/physreve.87.023103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 11/15/2012] [Indexed: 06/01/2023]
Abstract
Spatially resolved K-shell spectroscopy is used here to investigate the interaction of an ultrashort laser pulse (λ=800 nm, τ=40 fs) with a Ti foil under intense irradiation (Iλ(2)=2×10(18)Wμm(2)cm(-2)) and the following fast electron generation and transport into the target. The effect of laser pulse polarization (p, s, and circular) on the Kα yield and line shape is probed. The radial structure of intensity and width of the lines, obtained by a discretized Abel deconvolution algorithm, suggests an annular distribution of both the hot electron propagation into the target and the target temperature. An accurate modeling of Kα line shapes was performed, revealing temperature gradients, going from a few eV up to 15-20 eV, depending on the pulse polarization. Results are discussed in terms of mechanisms of hot electron generation and of their transport through the preplasma in front of the target.
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Affiliation(s)
- G Cristoforetti
- Intense Laser Irradiation Laboratory (ILIL), INO-CNR, Via G. Moruzzi 1, 56124 Pisa, Italy
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11
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Vauzour B, Santos JJ, Debayle A, Hulin S, Schlenvoigt HP, Vaisseau X, Batani D, Baton SD, Honrubia JJ, Nicolaï P, Beg FN, Benocci R, Chawla S, Coury M, Dorchies F, Fourment C, d'Humières E, Jarrot LC, McKenna P, Rhee YJ, Tikhonchuk VT, Volpe L, Yahia V. Relativistic high-current electron-beam stopping-power characterization in solids and plasmas: collisional versus resistive effects. PHYSICAL REVIEW LETTERS 2012; 109:255002. [PMID: 23368474 DOI: 10.1103/physrevlett.109.255002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Indexed: 06/01/2023]
Abstract
We present experimental and numerical results on intense-laser-pulse-produced fast electron beams transport through aluminum samples, either solid or compressed and heated by laser-induced planar shock propagation. Thanks to absolute K(α) yield measurements and its very good agreement with results from numerical simulations, we quantify the collisional and resistive fast electron stopping powers: for electron current densities of ≈ 8 × 10(10) A/cm(2) they reach 1.5 keV/μm and 0.8 keV/μm, respectively. For higher current densities up to 10(12)A/cm(2), numerical simulations show resistive and collisional energy losses at comparable levels. Analytical estimations predict the resistive stopping power will be kept on the level of 1 keV/μm for electron current densities of 10(14)A/cm(2), representative of the full-scale conditions in the fast ignition of inertially confined fusion targets.
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Affiliation(s)
- B Vauzour
- Univ Bordeaux, CNRS, CEA, CELIA, Centre Lasers Intenses et Applications, UMR 5107, F-33405 Talence, France
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12
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Labate L, Köster P, Levato T, Gizzi LA. A novel technique for single-shot energy-resolved 2D x-ray imaging of plasmas relevant for the inertial confinement fusion. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:103504. [PMID: 23126763 DOI: 10.1063/1.4759135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A novel x-ray diagnostic of laser-fusion plasmas is described, allowing 2D monochromatic images of hot, dense plasmas to be obtained in any x-ray photon energy range, over a large domain, on a single-shot basis. The device (named energy-encoded pinhole camera) is based upon the use of an array of many pinholes coupled to a large area CCD camera operating in the single-photon mode. The available x-ray spectral domain is only limited by the quantum efficiency of scientific-grade x-ray CCD cameras, thus extending from a few keV up to a few tens of keV. Spectral 2D images of the emitting plasma can be obtained at any x-ray photon energy provided that a sufficient number of photons had been collected at the desired energy. Results from recent inertial confinement fusion related experiments will be reported in order to detail the new diagnostic.
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Affiliation(s)
- L Labate
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Pisa, Italy.
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13
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Daido H, Nishiuchi M, Pirozhkov AS. Review of laser-driven ion sources and their applications. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:056401. [PMID: 22790586 DOI: 10.1088/0034-4885/75/5/056401] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
For many years, laser-driven ion acceleration, mainly proton acceleration, has been proposed and a number of proof-of-principle experiments have been carried out with lasers whose pulse duration was in the nanosecond range. In the 1990s, ion acceleration in a relativistic plasma was demonstrated with ultra-short pulse lasers based on the chirped pulse amplification technique which can provide not only picosecond or femtosecond laser pulse duration, but simultaneously ultra-high peak power of terawatt to petawatt levels. Starting from the year 2000, several groups demonstrated low transverse emittance, tens of MeV proton beams with a conversion efficiency of up to several percent. The laser-accelerated particle beams have a duration of the order of a few picoseconds at the source, an ultra-high peak current and a broad energy spectrum, which make them suitable for many, including several unique, applications. This paper reviews, firstly, the historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion. Secondly, we describe several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers. We pay special attention to relatively simple models of several acceleration regimes. The models connect the laser, plasma and proton/ion beam parameters, predicting important features, such as energy spectral shape, optimum conditions and scalings under these conditions for maximum ion energy, conversion efficiency, etc. The models also suggest possible ways to manipulate the proton/ion beams by tailoring the target and irradiation conditions. Thirdly, we review experimental results on proton/ion acceleration, starting with the description of driving lasers. We list experimental results and show general trends of parameter dependences and compare them with the theoretical predictions and simulations. The fourth topic includes a review of scientific, industrial and medical applications of laser-driven proton or ion sources, some of which have already been established, while the others are yet to be demonstrated. In most applications, the laser-driven ion sources are complementary to the conventional accelerators, exhibiting significantly different properties. Finally, we summarize the paper.
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Affiliation(s)
- Hiroyuki Daido
- Applied Laser Technology Institute, Tsuruga Head Office, Japan Atomic Energy Agency, Kizaki, Tsuruga-shi, Fukui-ken 914-8585, Japan.
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14
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Karataev P, Aryshev A, Boogert S, Howell D, Terunuma N, Urakawa J. First observation of the point spread function of optical transition radiation. PHYSICAL REVIEW LETTERS 2011; 107:174801. [PMID: 22107525 DOI: 10.1103/physrevlett.107.174801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Indexed: 05/31/2023]
Abstract
We represent the first experimental observation of the point spread function (PSF) of optical transition radiation (OTR) performed at KEK-Accelerator Test Facility extraction line. We have demonstrated that the PSF vertical polarization component has a central minimum with a two lobe distribution. However, the distribution width varied significantly with wavelength. We assume that we observed a severe effect from spherical or chromatic aberrations which are not taken into account in any existing theoretical model. We believe that the result of this work will encourage theoreticians to continue developing the theory as it is important for various transition radiation applications. Nonuniform distribution of the OTR PSF creates an opportunity for developing a submicrometer transverse beam size monitor.
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Affiliation(s)
- Pavel Karataev
- John Adams Institute at Royal Holloway, University of London, Egham, Surrey, TW20 0EX, United Kingdom.
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15
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Buffechoux S, Psikal J, Nakatsutsumi M, Romagnani L, Andreev A, Zeil K, Amin M, Antici P, Burris-Mog T, Compant-La-Fontaine A, d'Humières E, Fourmaux S, Gaillard S, Gobet F, Hannachi F, Kraft S, Mancic A, Plaisir C, Sarri G, Tarisien M, Toncian T, Schramm U, Tampo M, Audebert P, Willi O, Cowan TE, Pépin H, Tikhonchuk V, Borghesi M, Fuchs J. Hot electrons transverse refluxing in ultraintense laser-solid interactions. PHYSICAL REVIEW LETTERS 2010; 105:015005. [PMID: 20867457 DOI: 10.1103/physrevlett.105.015005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 01/21/2010] [Indexed: 05/29/2023]
Abstract
We have analyzed the coupling of ultraintense lasers (at ∼2×10{19} W/cm{2}) with solid foils of limited transverse extent (∼10 s of μm) by monitoring the electrons and ions emitted from the target. We observe that reducing the target surface area allows electrons at the target surface to be reflected from the target edges during or shortly after the laser pulse. This transverse refluxing can maintain a hotter, denser and more homogeneous electron sheath around the target for a longer time. Consequently, when transverse refluxing takes places within the acceleration time of associated ions, we observe increased maximum proton energies (up to threefold), increased laser-to-ion conversion efficiency (up to a factor 30), and reduced divergence which bodes well for a number of applications.
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Affiliation(s)
- S Buffechoux
- LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau, France
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16
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Habara H, Ohta K, Tanaka KA, Kumar GR, Krishnamurthy M, Kahaly S, Mondal S, Bhuyan MK, Rajeev R, Zheng J. Direct, absolute, and in situ measurement of fast electron transport via Cherenkov emission. PHYSICAL REVIEW LETTERS 2010; 104:055001. [PMID: 20366770 DOI: 10.1103/physrevlett.104.055001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Indexed: 05/29/2023]
Abstract
We present direct measurements of the absolute energy distribution of relativistic electrons generated in intense, femtosecond laser interaction with a solid. Cherenkov emission radiated by these electrons in a novel prism target is spectrally dispersed to obtain yield and energy distribution of electrons simultaneously. A crucial advance is the observation of high density electron current as predicted by particle simulations and its transport as it happens inside the target. In addition, the strong sheath potential present at the rear side of the target is inferred from a comparison of the electron spectra derived from Cherenkov light observation with that from a magnet spectrometer.
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Affiliation(s)
- Hideaki Habara
- Graduate School of Engineering, Osaka University, 2-1 Suita, 565-0871, Osaka, Japan
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17
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Debayle A, Tikhonchuk VT. Filamentation instability of a fast electron beam in a dielectric target. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:066404. [PMID: 19256959 DOI: 10.1103/physreve.78.066404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 10/16/2008] [Indexed: 05/27/2023]
Abstract
High-intensity laser-matter interaction is an efficient method for high-current relativistic electron beam production. At current densities exceeding a several kA microm{-2} , the beam propagation is maintained by an almost complete current neutralization by the target electrons. In such a geometry of two oppositely directed flows, beam instabilities can develop, depending on the target and the beam parameters. The present paper proposes an analytical description of the filamentation instability of an electron beam propagating through an insulator target. It is shown that the collisionless and resistive instabilities enter into competition with the ionization instability. This latter process is dominant in insulator targets where the field ionization by the fast beam provides free electrons for the neutralization current.
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Affiliation(s)
- A Debayle
- Centre Lasers Intenses et Applications, Université Bordeaux 1, CNRS, CEA, 351, Cours de la Libération, 33405 Talence Cedex, France
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18
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Antici P, Fuchs J, Borghesi M, Gremillet L, Grismayer T, Sentoku Y, d'Humières E, Cecchetti CA, Mancić A, Pipahl AC, Toncian T, Willi O, Mora P, Audebert P. Hot and cold electron dynamics following high-intensity laser matter interaction. PHYSICAL REVIEW LETTERS 2008; 101:105004. [PMID: 18851222 DOI: 10.1103/physrevlett.101.105004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Indexed: 05/26/2023]
Abstract
The characteristics of fast electrons laser accelerated from solids and expanding into a vacuum from the rear target surface have been measured via optical probe reflectometry. This allows access to the time- and space-resolved dynamics of the fast electron density and temperature and of the energy partition into bulk (cold) electrons. In particular, it is found that the density of the hot electrons on the target rear surface is bell shaped, and that their mean energy at the same location is radially homogeneous and decreases with the target thickness.
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Affiliation(s)
- P Antici
- LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau, France
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19
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Nakamura T, Mima K, Ter-Avetisyan S, Schnürer M, Sokollik T, Nickles PV, Sandner W. Lateral movement of a laser-accelerated proton source on the target's rear surface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:036407. [PMID: 18517533 DOI: 10.1103/physreve.77.036407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Indexed: 05/26/2023]
Abstract
The spatial dependence of proton acceleration at the rear surface of a target that is irradiated by high-contrast and ultraintense laser pulses is investigated. Lateral movement of the proton acceleration position at the rear surface is observed; this is tested by a two-pinhole measurement which results in the observation of protons with a narrow energy band. This drifting is only observed when relativistic-intensity laser pulses irradiate targets with a small preplasma at oblique incidence, as is confirmed by two-dimensional particle-in-cell simulations. This scenario of proton acceleration by the fast-moving sheath field leads to energy selection of the accelerated protons as a function of observing position.
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20
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Ter-Avetisyan S, Schnürer M, Sokollik T, Nickles PV, Sandner W, Reiss HR, Stein J, Habs D, Nakamura T, Mima K. Proton acceleration in the electrostatic sheaths of hot electrons governed by strongly relativistic laser-absorption processes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:016403. [PMID: 18351940 DOI: 10.1103/physreve.77.016403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 09/14/2007] [Indexed: 05/26/2023]
Abstract
Two different laser energy absorption mechanisms at the front side of a laser-irradiated foil have been found to occur, such that two distinct relativistic electron beams with different properties are produced. One beam arises from the ponderomotively driven electrons propagating in the laser propagation direction, and the other is the result of electrons driven by resonance absorption normal to the target surface. These properties become evident at the rear surface of the target, where they give rise to two spatially separated sources of ions with distinguishable characteristics when ultrashort (40fs) high-intensity laser pulses irradiate a foil at 45 degrees incidence. The laser pulse intensity and the contrast ratio are crucial. One can establish conditions such that one or the other of the laser energy absorption mechanisms is dominant, and thereby one can control the ion acceleration scenarios. The observations are confirmed by particle-in-cell (PIC) simulations.
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Affiliation(s)
- S Ter-Avetisyan
- Max-Born-Institute, Max-Born-Strasse 2a, D-12489 Berlin, Germany.
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21
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Kemp AJ, Fuchs J, Sentoku Y, Sotnikov V, Bakeman M, Antici P, Cowan TE. Emittance growth mechanisms for laser-accelerated proton beams. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:056401. [PMID: 17677176 DOI: 10.1103/physreve.75.056401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Revised: 01/05/2007] [Indexed: 05/16/2023]
Abstract
In recent experiments the transverse normalized rms emittance of laser-accelerated MeV ion beams was found to be < 0.002 mm mrad, which is at least 100 times smaller than the emittance of thermal ion sources used in accelerators [T. E. Cowan, Phys. Rev. Lett. 92, 204801 (2004)]. We investigate the origin for the low emittance of laser-accelerated proton beams by studying several candidates for emittance-growth mechanisms. As our main tools, we use analytical models and one- and two-dimensional particle-in-cell simulations that have been modified to include binary collisions between particles. We find that the dominant source of emittance is filamentation of the laser-generated hot electron jets that drive the ion acceleration. Cold electron-ion collisions that occur before ions are accelerated contribute less than ten percent of the final emittance. Our results are in qualitative agreement with the experiment, for which we present a refined analysis relating emittance to temperature, a better representative of the fundamental beam physics.
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Affiliation(s)
- Andreas J Kemp
- Physics Department, University of Nevada, Reno, Nevada 89557, USA
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22
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Klimo O, Tikhonchuk VT, Debayle A. High-current fast electron beam propagation in a dielectric target. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:016403. [PMID: 17358264 DOI: 10.1103/physreve.75.016403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Indexed: 05/14/2023]
Abstract
Recent experiments demonstrate an efficient transformation of high intensity laser pulse into a relativistic electron beam with a very high current density exceeding 10(12) A cm(-2). The propagation of such a beam inside the target is possible if its current is neutralized. This phenomenon is not well understood, especially in dielectric targets. In this paper, we study the propagation of high current density electron beam in a plastic target using a particle-in-cell simulation code. The code includes both ionization of the plastic and collisions of newborn electrons. The numerical results are compared with a relatively simple analytical model and a reasonable agreement is found. The temporal evolution of the beam velocity distribution, the spatial density profile, and the propagation velocity of the ionization front are analyzed and their dependencies on the beam density and energy are discussed. The beam energy losses are mainly due to the target ionization induced by the self-generated electric field and the return current. For the highest beam density, a two-stream instability is observed to develop in the plasma behind the ionization front and it contributes to the beam energy losses.
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Affiliation(s)
- Ondrej Klimo
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Brehova 7, 115 19 Praha 1, Czech Republic.
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