65 results found
Dover NP, Nishiuchi M, Sakaki H, et al., 2020, Demonstration of repetitive energetic proton generation by ultra-intense laser interaction with a tape target, High Energy Density Physics, Vol: 37, Pages: 100847-100847, ISSN: 1574-1818
Kondo K, Nishiuchi M, Sakaki H, et al., 2020, High-intensity laser-driven oxygen source from CW laser-heated titanium tape targets, Crystals, Vol: 10, Pages: 837-837, ISSN: 2073-4352
The interaction of high-intensity laser pulses with solid targets can be used as a highly charged, energetic heavy ion source. Normally, intrinsic contaminants on the target surface suppress the performance of heavy ion acceleration from a high-intensity laser–target interaction, resulting in preferential proton acceleration. Here, we demonstrate that CW laser heating of 5 µm titanium tape targets can remove contaminant hydrocarbons in order to expose a thin oxide layer on the metal surface, ideal for the generation of energetic oxygen beams. This is demonstrated by irradiating the heated targets with a PW class high-power laser at an intensity of 5 × 1021 W/cm2, showing enhanced acceleration of oxygen ions with a non-thermal-like distribution. Our new scheme using a CW laser-heated Ti tape target is promising for use as a moderate repetition energetic oxygen ion source for future applications.
Nishiuchi M, Sakaki H, Dover NP, et al., 2020, Ion species discrimination method by linear energy transfer measurement in Fujifilm BAS-SR imaging plate, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 91, ISSN: 0034-6748
Kiriyama H, Pirozhkov AS, Nishiuchi M, et al., 2020, Petawatt femtosecond laser pulses from titanium-doped sapphire crystal, Crystals, Vol: 10, Pages: 1-20
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Ultra-high intensity femtosecond lasers have now become excellent scientific tools for the study of extreme material states in small-scale laboratory settings. The invention of chirped-pulse amplification (CPA) combined with titanium-doped sapphire (Ti:sapphire) crystals have enabled realization of such lasers. The pursuit of ultra-high intensity science and applications is driving worldwide development of new capabilities. A petawatt (PW = 1015 W), femtosecond (fs = 10−15 s), repetitive (0.1 Hz), high beam quality J-KAREN-P (Japan Kansai Advanced Relativistic ENgineering Petawatt) Ti:sapphire CPA laser has been recently constructed and used for accelerating charged particles (ions and electrons) and generating coherent and incoherent ultra-short-pulse, high-energy photon (X-ray) radiation. Ultra-high intensities of 1022 W/cm2 with high temporal contrast of 10−12 and a minimal number of pre-pulses on target has been demonstrated with the J-KAREN-P laser. Here, worldwide ultra-high intensity laser development is summarized, the output performance and spatiotemporal quality improvement of the J-KAREN-P laser are described, and some experimental results are briefly introduced.
Kiriyama H, Pirozhkov AS, Nishiuchi M, et al., 2020, Status and progress of the J-KAREN-P high intensity laser system at QST, HIGH ENERGY DENSITY PHYSICS, Vol: 36, ISSN: 1574-1818
Nishiuchi M, Dover NP, Hata M, et al., 2020, Dynamics of laser-driven heavy-ion acceleration clarified by ion charge states, Physical Review Research, Vol: 2, Pages: 033081 – 1-033081 – 13, ISSN: 2643-1564
Motivated by the development of next-generation heavy-ion sources, we have investigated the ionization and acceleration dynamics of an ultraintense laser-driven high-Z silver target, experimentally, numerically, and analytically. Using a novel ion measurement technique allowing us to uniquely identify silver ions, we experimentally demonstrate generation of highly charged silver ions (Z∗=45+2−2) with energies of >20 MeV/nucleon (>2.2 GeV) from submicron silver targets driven by a laser with intensity 5×1021W/cm2, with increasing ion energy and charge state for decreasing target thickness. We show that although target pre-expansion by the unavoidable rising edge of state-of-the-art high-power lasers can limit proton energies, it is advantageous for heavy-ion acceleration. Two-dimensional particle-in-cell simulations show that the Joule heating in the target bulk results in a high temperature (∼10keV) solid density plasma, leading to the generation of high flux highly charged ions (Z∗=40+2−2, ≳10MeV/nucleon) via electron collisional ionization, which are extracted and accelerated with a small divergence by an extreme sheath field at the target rear. However, with reduced target thickness this favorable acceleration is degraded due to the target deformation via laser hole boring, which accompanies higher energy ions with higher charge states but in an uncontrollable manner. Our elucidation of the fundamental processes of high-intensity laser-driven ionization and ion acceleration provides a path for improving the control and parameters of laser-driven heavy-ion sources, a key component for next-generation heavy-ion accelerators.
Sakaki H, Yamashita T, Akagi T, et al., 2020, New algorithm using L1 regularization for measuring electron energy spectra, Review of Scientific Instruments, Vol: 91, Pages: 075116-075116, ISSN: 0034-6748
Dover NP, Nishiuchi M, Sakaki H, et al., 2020, Effect of small focus on electron heating and proton acceleration in ultrarelativistic laser-solid interactions, Physical Review Letters, Vol: 124, Pages: 084802 – 1-084802 – 7, ISSN: 0031-9007
Acceleration of particles from the interaction of ultraintense laser pulses up to 5×1021 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.
Passalidis S, Ettlinger OC, Hicks GS, et al., 2020, Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 8, ISSN: 2095-4719
King M, Butler NMH, Wilson R, et al., 2019, Role of magnetic field evolution on filamentary structure formation in intense laser-foil interactions, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 7, ISSN: 2095-4719
Kitagawa A, Fujita T, Hojo S, et al., 2018, Status of ion sources at the national institutes for quantum and radiological science and technology (QST), ISSN: 0094-243X
© 2018 Author(s). The National Institutes for Quantum and Radiological Science and Technology (QST) manages various types of ion sources for research and development in the fields of life sciences, medical and industrial applications, and fusion energy science. The QST is currently developing on electron cyclotron resonance ion sources, negative ion sources (ion sources for fusion and for tandem accelerators), ion sources for radioactive beams, laser ion sources, and miscellaneous ion sources. Its intra- and inter-institutional collaborations make QST a promising platform for future ion source technologies.
Pikuz SA, Faenov AY, Pikuz TA, et al., 2018, X-ray radiation properties of plasma under interaction of femtosecond laser pulses with ∼ 10<sup>22</sup> W/cm<sup>2</sup> intensities
© 2018 IEEE. Study of radiation properties of solid dense plasma irradiated by ultraintense lasers has a great interest both from fundamental physics and different application point of views. Recently upgraded petawatt J-KAREN-P laser together with precise focusing technique delivers 35 fs laser pulses of 1022 W/cm2 intensity into a micron-size focal spot on target. For such unprecedented intensities the application of high-resolution X-ray spectroscopy allows to investigate the ionization mechanisms and to measure the parameters of relativistic plasma from front and rear sides of moderate (Al) and high Z (Ti, Fe,) thin foil targets. Kinetic modeling of the spectra is used to estimate electron plasma density and temperature, demonstrating Te ∼2 keV for Ne ∼5e22 cm-3 in the hottest emission region. Thus, it is experimentally demonstrated for the first time that the laser pulse of over 1e21 W/cm2 intensity is absorbed neither in the solid density plasma nor in a pre-plasma of a common critical density, but in the matter of so called relativistic critical density. It is revealed how even small displacement of the target out of the optimal laser focus, as well the decrease in temporal contrast of the laser pulse, strongly reduce both the intensity of X-ray radiation and degree of plasma ionization. 2D PIC code simulations of femtosecond laser interaction with various materials are provided and compared with experimental results.
Kiriyama H, Pirozhkov AS, Nishiuchi M, et al., 2018, High-contrast high-intensity repetitive petawatt laser, OPTICS LETTERS, Vol: 43, Pages: 2595-2598, ISSN: 0146-9592
Kando M, Pirozhkov AS, Nishiuchi M, et al., 2018, Research on Laser Acceleration and Coherent X-Ray Generation Using J-KAREN-P Laser, Pages: 135-142, ISSN: 0930-8989
© 2018, Springer International Publishing AG. We present the progress on the upgrade status of the J-KAREN-P, which is a Ti: Sapphire laser aiming at the intensity of 1022 W/cm2 at the repetition rate of 0.1 Hz. The upgrade includes two pilot experiments in order to show the laser performance on target. The first experiment is to generate high-energy ions from thin-foil target. The second experiment is the high-order harmonic at a relativistic intensity. Currently, laser acceleration of protons is being tested and we have obtained 32 MeV protons from a 5-µm stainless steel target irradiated by a 14-J, 30-fs laser pulse. In addition, a joint program toward compact X-ray free-electron laser based on laser electron acceleration is presented briefly and the corresponding J-KAREN-P work is presented.
Alkhimova MA, Faenov AY, Pikuz TA, et al., 2018, X-ray emission from stainless steel foils irradiated by femtosecond petawatt laser pulses, 32nd International Conference on Interaction of Intense Energy Fluxes with Matter (ELBRUS), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
Kiriyama H, Nishiuchi M, Pirozhkov AS, et al., 2017, Latest achivements at the J-KAREN-P laser facility at QST, Pages: 1-3
© 2017 Institute of Electrical and Electronics Engineers Inc. All rights reserved. We report on a high-contrast, high-intensity Ti:sapphire chirped-pulse amplification system that incorporates a nonlinear preamplifier based on optical parametric chirpedpulse amplification (OPCPA). Chirped-pulses are amplified to 63 J at 0.1 Hz and compressed down to 30 fs. The temporal contrast is better than 3 x 10-12 on the sub-nanosecond timescale. A peak intensity of 1022 W/cm2 on target is reached by focusing a wavefront corrected 0.3 PW laser beam with an f/1.3 off-axis parabolic mirror.
Alkhimova MA, Faenov AY, Skobelev IY, et al., 2017, High resolution X-ray spectra of stainless steel foils irradiated by femtosecond laser pulses with ultra-relativistic intensities, OPTICS EXPRESS, Vol: 25, Pages: 29501-29511, ISSN: 1094-4087
Kiriyama H, Nishiuchi M, Pirozhkov AS, et al., 2017, 10<sup>22</sup>W/cm<sup>2</sup>, 0.1 Hz J-KAREN-P laser facility at QST, Pages: 1-2
© 2017 IEEE. Broadband-pulses are amplified to 63 J and compressed to 30 fs. A peak intensity of 1022 W/cm2 by focusing a 0.3 PW laser beam with an f/1.4 off-axis parabolic mirror is achievable on target.
Pirozhkov AS, Fukuda Y, Nishiuchi M, et al., 2017, Approaching the diffraction-limited, bandwidth-limited Petawatt, OPTICS EXPRESS, Vol: 25, Pages: 20486-20501, ISSN: 1094-4087
Faenov AY, Alkhimova MA, Pikuz TA, et al., 2017, The effect of laser contrast on generation of highly charged Fe ions by ultra-intense femtosecond laser pulses, APPLIED PHYSICS B-LASERS AND OPTICS, Vol: 123, ISSN: 0946-2171
Dover NP, Nishiuchi M, Sakaki H, et al., 2017, Scintillator-based transverse proton beam profiler for laser-plasma ion sources, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 88, ISSN: 0034-6748
Kiriyama H, Nishiuchi M, Pirozhkov AS, et al., 2017, Latest achivements at the J-KAREN-P laser facility at QST, Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Publisher: IEEE
Nishiuchi M, Kiriyama H, Pirozhkov AS, et al., 2017, Ion Acceleration Experiment by High Intensity (10(22) Wcm(-2)), High Contrast (10(-11)) J-KAREN-P Laser System at QST, Conference on Lasers and Electro-Optics Europe / European Quantum Electronics Conference (CLEO/Europe-EQEC), Publisher: IEEE
Kiriyama H, Nishiuchi M, Pirozhkov AS, et al., 2017, J-KAREN-P Laser Facility at QST: High Contrast, High Intensity Petawatt OPCPA/Ti:sapphire Hybrid Laser System, Conference on Lasers and Electro-Optics Europe / European Quantum Electronics Conference (CLEO/Europe-EQEC), Publisher: IEEE
Nishiuchi M, Kiriyama H, Sakaki H, et al., 2017, High Contrast High Intensity Petawatt J-KAREN-P Laser facility at QST, Conference on Research Using Extreme Light - Entering New Frontiers with Petawatt-Class Lasers III, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Kiriyama H, Nishiuchi M, Pirozhkov AS, et al., 2017, 10(22)W/cm(2), 0.1 Hz J-KAREN-P laser facility at QST, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Ting A, Hafizi B, Helle M, et al., 2016, Staging and Laser Acceleration of Ions in Underdense Plasma, 17th Advanced Accelerator Concepts Workshop (AAC), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
Chen Y-H, Helle M, Ting A, et al., 2016, Laser Acceleration of Protons with an Optically Shaped, Near-Critical Hydrogen Gas Target, 17th Advanced Accelerator Concepts Workshop (AAC), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
Pogorelsky IV, Babzien M, Ben-Zvi I, et al., 2016, Extending laser plasma accelerators into the mid-IR spectral domain with a next-generation ultra-fast CO2 laser, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 58, ISSN: 0741-3335
King M, Gray RJ, Powell HW, et al., 2016, Ion acceleration and plasma jet formation in ultra-thin foils undergoing expansion and relativistic transparency, 2nd Workshop on European Advanced Accelerator Concepts (EAAC), Publisher: Elsevier, Pages: 163-166, ISSN: 0168-9002
At sufficiently high laser intensities, the rapid heating to relativistic velocities and resulting decompression of plasma electrons in an ultra-thin target foil can result in the target becoming relativistically transparent to the laser light during the interaction. Ion acceleration in this regime is strongly affected by the transition from an opaque to a relativistically transparent plasma. By spatially resolving the laser-accelerated proton beam at near-normal laser incidence and at an incidence angle of 30°, we identify characteristic features both experimentally and in particle-in-cell simulations which are consistent with the onset of three distinct ion acceleration mechanisms: sheath acceleration; radiation pressure acceleration; and transparency-enhanced acceleration. The latter mechanism occurs late in the interaction and is mediated by the formation of a plasma jet extending into the expanding ion population. The effect of laser incident angle on the plasma jet is explored.
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