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Sawada H, Sentoku Y, Yabuuchi T, Zastrau U, Förster E, Beg FN, Chen H, Kemp AJ, McLean HS, Patel PK, Ping Y. Monochromatic 2D Kα Emission Images Revealing Short-Pulse Laser Isochoric Heating Mechanism. PHYSICAL REVIEW LETTERS 2019; 122:155002. [PMID: 31050520 DOI: 10.1103/physrevlett.122.155002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/10/2019] [Indexed: 06/09/2023]
Abstract
The rapid heating of a thin titanium foil by a high intensity, subpicosecond laser is studied by using a 2D narrow-band x-ray imaging and x-ray spectroscopy. A novel monochromatic imaging diagnostic tuned to 4.51 keV Ti Kα was used to successfully visualize a significantly ionized area (⟨Z⟩>17±1) of the solid density plasma to be within a ∼35 μm diameter spot in the transverse direction and 2 μm in depth. The measurements and a 2D collisional particle-in-cell simulation reveal that, in the fast isochoric heating of solid foil by an intense laser light, such a high ionization state in solid titanium is achieved by thermal diffusion from the hot preplasma in a few picoseconds after the pulse ends. The shift of Kα and formation of a missing Kα cannot be explained with the present atomic physics model. The measured Kα image is reproduced only when a phenomenological model for the Kα shift with a threshold ionization of ⟨Z⟩=17 is included. This work reveals how the ionization state and electron temperature of the isochorically heated nonequilibrium plasma are independently increased.
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Affiliation(s)
- H Sawada
- University of Nevada Reno, Reno, Nevada 89557-0220, USA
| | - Y Sentoku
- Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan
| | - T Yabuuchi
- RIKEN SPring-8 Center, Hyogo 679-5198, Japan
| | - U Zastrau
- European XFEL, 22869, Schenefeld, Germany
| | - E Förster
- IOQ, Friedrich-Schiller University of Jena, 07743, Jena, Germany
- Helmholtz Institute at Jena, 07743, Jena, Germany
| | - F N Beg
- University of California San Diego, La Jolla, California 92093-0417, USA
| | - H Chen
- Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA
| | - A J Kemp
- Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA
| | - H S McLean
- Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA
| | - P K Patel
- Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA
| | - Y Ping
- Lawrence Livermore National Laboratory, Livermore, California 94550-9234, USA
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Ivanov VV, Maximov AV, Swanson KJ, Wong NL, Sarkisov GS, Wiewior PP, Astanovitskiy AL, Covington AM. Experimental platform for investigations of high-intensity laser plasma interactions in the magnetic field of a pulsed power generator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:033504. [PMID: 29604737 DOI: 10.1063/1.5016973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An experimental platform for the studying of high-intensity laser plasma interactions in strong magnetic fields has been developed based on the 1 MA Zebra pulsed power generator coupled with the 50-TW Leopard laser. The Zebra generator produces 100-300 T longitudinal and transverse magnetic fields with different types of loads. The Leopard laser creates plasma at an intensity of 1019 W/cm2 in the magnetic field of coil loads. Focusing and targeting systems are integrated in the vacuum chamber of the pulsed power generator and protected from the plasma debris and strong mechanical shock. The first experiments with plasma at laser intensity >2 × 1018 W/cm2 demonstrated collimation of the laser produced plasma in the axial magnetic field strength >100 T.
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Affiliation(s)
- V V Ivanov
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - A V Maximov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - K J Swanson
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - N L Wong
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - G S Sarkisov
- Raytheon Ktech, Albuquerque, New Mexico 87123, USA
| | - P P Wiewior
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - A L Astanovitskiy
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - A M Covington
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Sawada H, Daykin T, McLean HS, Chen H, Patel PK, Ping Y, Pérez F. Two-color monochromatic x-ray imaging with a single short-pulse laser. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:063502. [PMID: 28668008 DOI: 10.1063/1.4985729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Simultaneous monochromatic crystal imaging at 4.5 and 8.0 keV with x-rays produced by a single short-pulse laser is presented. A layered target consisting of thin foils of titanium and copper glued together is irradiated by the 50 TW Leopard short-pulse laser housed at the Nevada Terawatt Facility. Laser-accelerated MeV fast electrons transmitting through the target induce Kα fluorescence from both foils. Two energy-selective curved crystals in the imaging diagnostic form separate monochromatic images on a single imaging detector. The experiment demonstrates simultaneous two-color monochromatic imaging of the foils on a single detector as well as Kα x-ray production at two different photon energies with a single laser beam. Application of the diagnostic technique to x-ray radiography of a high density plasma is also presented.
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Affiliation(s)
- H Sawada
- Department of Physics, University of Nevada Reno, Reno, Nevada 89557, USA
| | - T Daykin
- Department of Physics, University of Nevada Reno, Reno, Nevada 89557, USA
| | - H S McLean
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H Chen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P K Patel
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Y Ping
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - F Pérez
- Ecole Polytechnique, CNRS, 91761 Palaiseau, France
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Ivanov VV, Anderson AA, Begishev IA. Four-color laser diagnostics for Z-pinch and laser-produced plasma. APPLIED OPTICS 2016; 55:498-501. [PMID: 26835923 DOI: 10.1364/ao.55.000498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Four-color laser diagnostics were developed for Z-pinch and laser plasma at the 1 MA pulsed power generator. Four harmonics of the Nd:YAG laser at wavelengths of 1064, 532, 266, and 213 nm were produced during the cascade conversion in three nonlinear crystals and propagated together in one beampath. Deep UV probing allows better penetration of the dense plasma. Laser probing at four wavelengths allows observation of plasma in a wide range of densities in one shot of the diagnostic laser. Examples of four-color laser shadowgraphy and interferometry of the wire-array load and laser plasma interaction are presented and discussed.
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Sarkisov GS, Ivanov VV, Leblanc P, Sentoku Y, Yates K, Wiewior P, Chalyy O, Astanovitskiy A, Bychenkov VY, Jobe D, Spielman RB. Propagation of a laser-driven relativistic electron beam inside a solid dielectric. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:036412. [PMID: 23031038 DOI: 10.1103/physreve.86.036412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/09/2012] [Indexed: 06/01/2023]
Abstract
Laser probe diagnostics: shadowgraphy, interferometry, and polarimetry were used for a comprehensive characterization of ionization wave dynamics inside a glass target induced by a laser-driven, relativistic electron beam. Experiments were done using the 50-TW Leopard laser at the University of Nevada, Reno. We show that for a laser flux of ∼2 × 10(18) W/cm2 a hemispherical ionization wave propagates at c/3 for 10 ps and has a smooth electron-density distribution. The maximum free-electron density inside the glass target is ∼2 × 10(19) cm-3, which corresponds to an ionization level of ∼0.1%. Magnetic fields and electric fields do not exceed ∼15 kG and ∼1 MV/cm, respectively. The electron temperature has a hot, ringlike structure with a maximum of ∼0.7 eV. The topology of the interference phase shift shows the signature of the "fountain effect", a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields driven by laser. The very low ionization observed after the laser heating pulse suggests a fast recombination on the sub-ps time scale.
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Affiliation(s)
- G S Sarkisov
- Raytheon Ktech, 1300 Eubank Blvd, Albuquerque, New Mexico 87123, USA
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Ivanov VV, Hakel P, Mancini RC, Chittenden JP, Anderson A, Durmaz T, Wiewior P, Papp D, Altemara SD, Astanovitskiy AL, Chalyy O. Measurement of the ionization state and electron temperature of plasma during the ablation stage of a wire-array Z pinch using absorption spectroscopy. PHYSICAL REVIEW LETTERS 2011; 106:225005. [PMID: 21702609 DOI: 10.1103/physrevlett.106.225005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Indexed: 05/31/2023]
Abstract
Wire-array plasmas were investigated in the nonradiative ablation stage via x-ray absorption spectroscopy. A laser-produced Sm plasma was used to backlight Al wire arrays. The Sm spectrum was simultaneously observed by two spectrometers: one recorded the unattenuated spectrum and the other the transmission spectrum with 1.45-1.55 keV K-shell absorption lines. Analysis of absorption spectra revealed electron temperature in the range of 10-30 eV and the presence of F-, O-, N- and C-like Al ions in the absorbing plasma. A comparison of this electron temperature with the postprocessed absorption spectra of a 2D MHD simulation yields results in general agreement with the data analysis.
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Affiliation(s)
- V V Ivanov
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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