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Sawada H, Fujioka S, Hosoda T, Zhang Z, Arikawa Y, Nagatomo H, Nishimura H, Sunahara A, Theobald W, Patel PK, Beg FN. Development of 4.5 keV monochromatic X-ray radiography using the high-energy, picosecond LFEX laser. ACTA ACUST UNITED AC 2016. [DOI: 10.1088/1742-6596/717/1/012112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Patel PK, Vyas BA. Evaluation of Antiurolithiatic Effect of Pedalium murex Fruit Extract in Ethylene Glycol-induced Nephrolithiasis in Rat. Indian J Pharm Sci 2016. [DOI: 10.4172/pharmaceutical-sciences.1000108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Higginson DP, Link A, Sawada H, Wilks SC, Bartal T, Chawla S, Chen CD, Flippo KA, Jarrott LC, Key MH, McLean HS, Patel PK, Pérez F, Wei MS, Beg FN. High-contrast laser acceleration of relativistic electrons in solid cone-wire targets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:063112. [PMID: 26764843 DOI: 10.1103/physreve.92.063112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Indexed: 06/05/2023]
Abstract
The consequences of small scale-length precursor plasmas on high-intensity laser-driven relativistic electrons are studied via experiments and simulations. Longer scale-length plasmas are shown to dramatically increase the efficiency of electron acceleration, yet, if too long, they reduce the coupling of these electrons into the solid target. Evidence for the existence of an optimal plasma scale-length is presented and estimated to be from 1 to 5μm. Experiments on the Trident laser (I=5×10(19)W/cm(2)) diagnosed via Kα emission from Cu wires attached to Au cones are quantitively reproduced using 2D particle-in-cell simulations that capture the full temporal and spatial scale of the nonlinear laser interaction and electron transport. The simulations indicate that 32%±8%(6.5%±2%) of the laser energy is coupled into electrons of all energies (1-3 MeV) reaching the inner cone tip and that, with an optimized scale-length, this could increase to 35% (9%).
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Casey DT, Milovich JL, Smalyuk VA, Clark DS, Robey HF, Pak A, MacPhee AG, Baker KL, Weber CR, Ma T, Park HS, Döppner T, Callahan DA, Haan SW, Patel PK, Peterson JL, Hoover D, Nikroo A, Yeamans CB, Merrill FE, Volegov PL, Fittinghoff DN, Grim GP, Edwards MJ, Landen OL, Lafortune KN, MacGowan BJ, Widmayer CC, Sayre DB, Hatarik R, Bond EJ, Nagel SR, Benedetti LR, Izumi N, Khan S, Bachmann B, Spears BK, Cerjan CJ, Gatu Johnson M, Frenje JA. Improved Performance of High Areal Density Indirect Drive Implosions at the National Ignition Facility using a Four-Shock Adiabat Shaped Drive. PHYSICAL REVIEW LETTERS 2015; 115:105001. [PMID: 26382681 DOI: 10.1103/physrevlett.115.105001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Indexed: 06/05/2023]
Abstract
Hydrodynamic instabilities can cause capsule defects and other perturbations to grow and degrade implosion performance in ignition experiments at the National Ignition Facility (NIF). Here, we show the first experimental demonstration that a strong unsupported first shock in indirect drive implosions at the NIF reduces ablation front instability growth leading to a 3 to 10 times higher yield with fuel ρR>1 g/cm(2). This work shows the importance of ablation front instability growth during the National Ignition Campaign and may provide a path to improved performance at the high compression necessary for ignition.
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Kemp GE, Link A, Ping Y, Ayers S, Patel PK. Commissioning of a frequency-resolved optical gating system at the OMEGA EP laser facility: SpecFROG. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:093501. [PMID: 26429437 DOI: 10.1063/1.4929868] [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
We present the design and commissioning of a new single-shot, frequency-resolved optical gating system on the OMEGA EP laser facility - dubbed "SpecFROG" - for characterizing the instantaneous intensity and phase of ∼10 ps pulses used to study ultra-intense laser-plasma interactions. A polarization-gating geometry is employed to ensure tha the diagnostic is broadband and has unambiguous time directionality. SpecFROG is capable of characterizing ∼10 s of mJ pulses with durations between 0.5-25 ps with ≲285 fs geometrical temporal blurring and ∼0.1% spectral shift resolutions over an adjustable total spectral shifting window of ∼15% of the carrier wavelength λo; configurations currently exist for both the fundamental (1ω, λo = 1.054 μm) and second harmonic (2ω, λo = 0.527 μm) of the EP pulse. Initial specular reflectivity measurements of the ∼1 kJ, ∼10 ps OMEGA EP laser off solid density aluminum targets suggest drastically different scalings for specular pulse properties compared to picosecond-scale pulses of comparable intensities.
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Döppner T, Callahan DA, Hurricane OA, Hinkel DE, Ma T, Park HS, Berzak Hopkins LF, Casey DT, Celliers P, Dewald EL, Dittrich TR, Haan SW, Kritcher AL, MacPhee A, Le Pape S, Pak A, Patel PK, Springer PT, Salmonson JD, Tommasini R, Benedetti LR, Bond E, Bradley DK, Caggiano J, Church J, Dixit S, Edgell D, Edwards MJ, Fittinghoff DN, Frenje J, Gatu Johnson M, Grim G, Hatarik R, Havre M, Herrmann H, Izumi N, Khan SF, Kline JL, Knauer J, Kyrala GA, Landen OL, Merrill FE, Moody J, Moore AS, Nikroo A, Ralph JE, Remington BA, Robey HF, Sayre D, Schneider M, Streckert H, Town R, Turnbull D, Volegov PL, Wan A, Widmann K, Wilde CH, Yeamans C. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility. PHYSICAL REVIEW LETTERS 2015; 115:055001. [PMID: 26274424 DOI: 10.1103/physrevlett.115.055001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 06/04/2023]
Abstract
We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.
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Ma T, Hurricane OA, Callahan DA, Barrios MA, Casey DT, Dewald EL, Dittrich TR, Döppner T, Haan SW, Hinkel DE, Berzak Hopkins LF, Le Pape S, MacPhee AG, Pak A, Park HS, Patel PK, Remington BA, Robey HF, Salmonson JD, Springer PT, Tommasini R, Benedetti LR, Bionta R, Bond E, Bradley DK, Caggiano J, Celliers P, Cerjan CJ, Church JA, Dixit S, Dylla-Spears R, Edgell D, Edwards MJ, Field J, Fittinghoff DN, Frenje JA, Gatu Johnson M, Grim G, Guler N, Hatarik R, Herrmann HW, Hsing WW, Izumi N, Jones OS, Khan SF, Kilkenny JD, Knauer J, Kohut T, Kozioziemski B, Kritcher A, Kyrala G, Landen OL, MacGowan BJ, Mackinnon AJ, Meezan NB, Merrill FE, Moody JD, Nagel SR, Nikroo A, Parham T, Ralph JE, Rosen MD, Rygg JR, Sater J, Sayre D, Schneider MB, Shaughnessy D, Spears BK, Town RPJ, Volegov PL, Wan A, Widmann K, Wilde CH, Yeamans C. Thin shell, high velocity inertial confinement fusion implosions on the national ignition facility. PHYSICAL REVIEW LETTERS 2015; 114:145004. [PMID: 25910132 DOI: 10.1103/physrevlett.114.145004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 06/04/2023]
Abstract
Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 μm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Early results have shown good repeatability, with up to 1/2 the neutron yield coming from α-particle self-heating.
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Vaisseau X, Debayle A, Honrubia JJ, Hulin S, Morace A, Nicolaï P, Sawada H, Vauzour B, Batani D, Beg FN, Davies JR, Fedosejevs R, Gray RJ, Kemp GE, Kerr S, Li K, Link A, McKenna P, McLean HS, Mo M, Patel PK, Park J, Peebles J, Rhee YJ, Sorokovikova A, Tikhonchuk VT, Volpe L, Wei M, Santos JJ. Enhanced relativistic-electron-beam energy loss in warm dense aluminum. PHYSICAL REVIEW LETTERS 2015; 114:095004. [PMID: 25793822 DOI: 10.1103/physrevlett.114.095004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 06/04/2023]
Abstract
Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11} A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.
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Al Awaidy ST, Al Obeidani I, Bawikar S, Al Mahrouqi S, Al Busaidy SS, Al Baqlani S, Patel PK. Dengue epidemiological trend in Oman: a 13-year national surveillance and strategic proposition of imported cases. Trop Doct 2014; 44:190-5. [PMID: 24994569 DOI: 10.1177/0049475514541650] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dengue fever has emerged as a major public health problem globally in the past three decades. A 13-year national surveillance data analysis was done to describe the epidemiology and its trend of dengue disease in Oman reported between 2001 and 2013. Laboratory-confirmed dengue virus infections reported were studied retrospectively during the study period. A total of 64 laboratory confirmed cases were reported. All the patients contracted the disease during their visit to South-East Asian countries, hence classified as imported cases. The majority of the cases were reported in the year 2012 (23.4%). The most important clinical characteristics were fever (90.6%), myalgia (35.9%) and rash/petechial rash (20.3%). Thrombocytopenia was seen in 31.2% of the study subjects. The mortality was nearly 4.6% and all other patients made a full recovery. The most effective measure for travellers is taking precautions to avoid mosquito bites.
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Sawada H, Wei MS, Chawla S, Morace A, Akli K, Yabuuchi T, Nakanii N, Key MH, Patel PK, Mackinnon AJ, McLean HS, Stephens RB, Beg FN. Investigation of fast-electron-induced Kα x rays in laser-produced blow-off plasma. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:033105. [PMID: 24730954 DOI: 10.1103/physreve.89.033105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Indexed: 06/03/2023]
Abstract
Refluxing of fast electrons generated by high-intensity, short-pulse lasers was investigated by measuring electron-induced Kα x rays from a buried tracer layer. Using planar foils of Au/Cu/CH, the 150-J, 0.7-ps TITAN short-pulse laser was focused on the gold foil to generate fast electrons and the 3-ns, 300-J long pulse beam irradiated on the CH side to create expanding plasma as a conducting medium. By delaying the short-pulse beam timing from the long pulse laser irradiation, the plasma size was varied to change electron refluxing in the target rear. The total yields and two-dimensional images of 8.05-keV Cu-Kα x ray were recorded with an x-ray spectrometer and two monochromatic crystal imagers. The measurements show that the integrated yields decrease by a factor of 10 from refluxing to the nonrefluxing limit. Similar radial profiles of the Kα images in the rear were observed at all delays. Hybrid-particle-in-cell simulations using plasma profiles calculated by a radiation-hydrodynamic code HYDRA agree well with the measured Kα yields. The simulations suggest that conducting plasma with the size of ∼300 μm in the laser direction and ∼600 μm in the lateral direction at the density of 2 × 1020 1/cm3 is sufficiently large to prevent electrons from refluxing in the target. The parameters found in this study can be useful in designing experiments utilizing a Kα x-ray source in refluxing regime or a tracer layer in nonrefluxing regime.
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Park HS, Hurricane OA, Callahan DA, Casey DT, Dewald EL, Dittrich TR, Döppner T, Hinkel DE, Berzak Hopkins LF, Le Pape S, Ma T, Patel PK, Remington BA, Robey HF, Salmonson JD, Kline JL. High-adiabat high-foot inertial confinement fusion implosion experiments on the national ignition facility. PHYSICAL REVIEW LETTERS 2014; 112:055001. [PMID: 24580603 DOI: 10.1103/physrevlett.112.055001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Indexed: 06/03/2023]
Abstract
This Letter reports on a series of high-adiabat implosions of cryogenic layered deuterium-tritium (DT) capsules indirectly driven by a "high-foot" laser drive pulse at the National Ignition Facility. High-foot implosions have high ablation velocities and large density gradient scale lengths and are more resistant to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot. Indeed, the observed hot spot mix in these implosions was low and the measured neutron yields were typically 50% (or higher) of the yields predicted by simulation. On one high performing shot (N130812), 1.7 MJ of laser energy at a peak power of 350 TW was used to obtain a peak hohlraum radiation temperature of ∼300 eV. The resulting experimental neutron yield was (2.4±0.05)×10(15) DT, the fuel ρR was (0.86±0.063) g/cm2, and the measured Tion was (4.2±0.16) keV, corresponding to 8 kJ of fusion yield, with ∼1/3 of the yield caused by self-heating of the fuel by α particles emitted in the initial reactions. The generalized Lawson criteria, an ignition metric, was 0.43 and the neutron yield was ∼70% of the value predicted by simulations that include α-particle self-heating.
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Dittrich TR, Hurricane OA, Callahan DA, Dewald EL, Döppner T, Hinkel DE, Berzak Hopkins LF, Le Pape S, Ma T, Milovich JL, Moreno JC, Patel PK, Park HS, Remington BA, Salmonson JD, Kline JL. Design of a high-foot high-adiabat ICF capsule for the national ignition facility. PHYSICAL REVIEW LETTERS 2014; 112:055002. [PMID: 24580604 DOI: 10.1103/physrevlett.112.055002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Indexed: 06/03/2023]
Abstract
The National Ignition Campaign's [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] point design implosion has achieved DT neutron yields of 7.5×10(14) neutrons, inferred stagnation pressures of 103 Gbar, and inferred areal densities (ρR) of 0.90 g/cm2 (shot N111215), values that are lower than 1D expectations by factors of 10×, 3.3×, and 1.5×, respectively. In this Letter, we present the design basis for an inertial confinement fusion capsule using an alternate indirect-drive pulse shape that is less sensitive to issues that may be responsible for this lower than expected performance. This new implosion features a higher radiation temperature in the "foot" of the pulse, three-shock pulse shape resulting in an implosion that has less sensitivity to the predicted ionization state of carbon, modestly lower convergence ratio, and significantly lower ablation Rayleigh-Taylor instability growth than that of the NIC point design capsule. The trade-off with this new design is a higher fuel adiabat that limits both fuel compression and theoretical capsule yield. The purpose of designing this capsule is to recover a more ideal one-dimensional implosion that is in closer agreement to simulation predictions. Early experimental results support our assertions since as of this Letter, a high-foot implosion has obtained a record DT yield of 2.4×10(15) neutrons (within ∼70% of 1D simulation) with fuel ρR=0.84 g/cm2 and an estimated ∼1/3 of the yield coming from α-particle self-heating.
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Pérez F, Kemp AJ, Divol L, Chen CD, Patel PK. Deflection of MeV electrons by self-generated magnetic fields in intense laser-solid interactions. PHYSICAL REVIEW LETTERS 2013; 111:245001. [PMID: 24483668 DOI: 10.1103/physrevlett.111.245001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/09/2013] [Indexed: 06/03/2023]
Abstract
We show that the interaction of relativistic-intensity, picosecond laser pulses with solid targets is affected by the reflected light through the strong currents and 10(4) T magnetic fields it produces. Three-dimensional particle-in-cell simulations, with the axisymmetry broken by a small angle of incidence, show that these magnetic fields deflect the laser-accelerated electrons away from the incident laser axis. This directly impacts the interpretation of electron divergence and directionality in applications such as laser-driven ion acceleration or fast-ignition inertial fusion.
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Smalyuk VA, Atherton LJ, Benedetti LR, Bionta R, Bleuel D, Bond E, Bradley DK, Caggiano J, Callahan DA, Casey DT, Celliers PM, Cerjan CJ, Clark D, Dewald EL, Dixit SN, Döppner T, Edgell DH, Edwards MJ, Frenje J, Gatu-Johnson M, Glebov VY, Glenn S, Glenzer SH, Grim G, Haan SW, Hammel BA, Hartouni EP, Hatarik R, Hatchett S, Hicks DG, Hsing WW, Izumi N, Jones OS, Key MH, Khan SF, Kilkenny JD, Kline JL, Knauer J, Kyrala GA, Landen OL, Le Pape S, Lindl JD, Ma T, MacGowan BJ, Mackinnon AJ, MacPhee AG, McNaney J, Meezan NB, Moody JD, Moore A, Moran M, Moses EI, Pak A, Parham T, Park HS, Patel PK, Petrasso R, Ralph JE, Regan SP, Remington BA, Robey HF, Ross JS, Spears BK, Springer PT, Suter LJ, Tommasini R, Town RP, Weber SV, Widmann K. Performance of high-convergence, layered DT implosions with extended-duration pulses at the National Ignition Facility. PHYSICAL REVIEW LETTERS 2013; 111:215001. [PMID: 24313493 DOI: 10.1103/physrevlett.111.215001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 06/02/2023]
Abstract
Radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm2, representing a significant step from previously measured ~1.0 g/cm2 toward a goal of 1.5 g/cm2. Future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF.
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Ma T, Patel PK, Izumi N, Springer PT, Key MH, Atherton LJ, Benedetti LR, Bradley DK, Callahan DA, Celliers PM, Cerjan CJ, Clark DS, Dewald EL, Dixit SN, Döppner T, Edgell DH, Epstein R, Glenn S, Grim G, Haan SW, Hammel BA, Hicks D, Hsing WW, Jones OS, Khan SF, Kilkenny JD, Kline JL, Kyrala GA, Landen OL, Le Pape S, MacGowan BJ, Mackinnon AJ, MacPhee AG, Meezan NB, Moody JD, Pak A, Parham T, Park HS, Ralph JE, Regan SP, Remington BA, Robey HF, Ross JS, Spears BK, Smalyuk V, Suter LJ, Tommasini R, Town RP, Weber SV, Lindl JD, Edwards MJ, Glenzer SH, Moses EI. Onset of hydrodynamic mix in high-velocity, highly compressed inertial confinement fusion implosions. PHYSICAL REVIEW LETTERS 2013; 111:085004. [PMID: 24010449 DOI: 10.1103/physrevlett.111.085004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Indexed: 06/02/2023]
Abstract
Deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility have demonstrated yields ranging from 0.8 to 7×10(14), and record fuel areal densities of 0.7 to 1.3 g/cm2. These implosions use hohlraums irradiated with shaped laser pulses of 1.5-1.9 MJ energy. The laser peak power and duration at peak power were varied, as were the capsule ablator dopant concentrations and shell thicknesses. We quantify the level of hydrodynamic instability mix of the ablator into the hot spot from the measured elevated absolute x-ray emission of the hot spot. We observe that DT neutron yield and ion temperature decrease abruptly as the hot spot mix mass increases above several hundred ng. The comparison with radiation-hydrodynamic modeling indicates that low mode asymmetries and increased ablator surface perturbations may be responsible for the current performance.
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Friesen H, Tiedje HF, Hey DS, Mo MZ, Beaudry A, Fedosejevs R, Tsui YY, Mackinnon A, McLean HS, Patel PK. Kirkpatrick-Baez microscope for hard X-ray imaging of fast ignition experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:023704. [PMID: 23464215 DOI: 10.1063/1.4776670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A Kirkpatrick-Baez X-ray microscope has been developed for use on the Titan laser facility at the Lawrence Livermore National Laboratory in Fast Ignition experiments. It was developed as a broadband alternative to narrow band Bragg crystal imagers for imaging Kα emission from tracer layers. A re-entrant design is employed which allows for alignment from outside the chamber. The mirrors are coated with Pt and operate at a grazing incident angle of 0.5° providing higher resolution than an equal brightness pinhole and sufficient bandwidth to image thermally shifted characteristic Kα emission from heated Cu tracer layers in Fast Ignition experiments. The superpolished substrates (<1 Å rms roughness) had a final visible wavelength roughness of 1.7 Å after coating, and exhibited a reflectivity corresponding to an X-ray wavelength roughness of 7 ± 1 Å. A unique feature of this design is that during experiments, the unfiltered direct signal along with the one-dimensional reflections are retained on the detector in order to enable a live indication of alignment and incident angle. The broad spectral window from 4 to 9 keV enables simultaneous observation of emission from several spectral regions of interest, which has been demonstrated to be particularly useful for cone-wire targets. An experimentally measured resolution of 15 μm has been obtained at the center of the field of view.
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Chawla S, Wei MS, Mishra R, Akli KU, Chen CD, McLean HS, Morace A, Patel PK, Sawada H, Sentoku Y, Stephens RB, Beg FN. Effect of target material on fast-electron transport and resistive collimation. PHYSICAL REVIEW LETTERS 2013; 110:025001. [PMID: 23383907 DOI: 10.1103/physrevlett.110.025001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Indexed: 06/01/2023]
Abstract
The effect of target material on fast-electron transport is investigated using a high-intensity (0.7 ps, 10(20) W/cm2) laser pulse irradiated on multilayered solid Al targets with embedded transport (Au, Mo, Al) and tracer (Cu) layers, backed with millimeter-thick carbon foils to minimize refluxing. We consistently observed a more collimated electron beam (36% average reduction in fast-electron induced Cu Kα spot size) using a high- or mid-Z (Au or Mo) layer compared to Al. All targets showed a similar electron flux level in the central spot of the beam. Two-dimensional collisional particle-in-cell simulations showed formation of strong self-generated resistive magnetic fields in targets with a high-Z transport layer that suppressed the fast-electron beam divergence; the consequent magnetic channels guided the fast electrons to a smaller spot, in good agreement with experiments. These findings indicate that fast-electron transport can be controlled by self-generated resistive magnetic fields and may have important implications to fast ignition.
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Vyas VK, Bhatt HG, Patel PK, Jalu J, Chintha C, Gupta N, Ghate M. CoMFA and CoMSIA studies on C-aryl glucoside SGLT2 inhibitors as potential anti-diabetic agents. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2013; 24:519-551. [PMID: 23305412 DOI: 10.1080/1062936x.2012.751553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
SGLT2 has become a target of therapeutic interest in diabetes research. CoMFA and CoMSIA studies were performed on C-aryl glucoside SGLT2 inhibitors (180 analogues) as potential anti-diabetic agents. Three different alignment strategies were used for the compounds. The best CoMFA and CoMSIA models were obtained by means of Distill rigid body alignment of training and test sets, and found statistically significant with cross-validated coefficients (q²) of 0.602 and 0.618, respectively, and conventional coefficients (r²) of 0.905 and 0.902, respectively. Both models were validated by a test set of 36 compounds giving satisfactory predicted correlation coefficients (r² pred) of 0.622 and 0.584 for CoMFA and CoMSIA models, respectively. A comparison was made with earlier 3D QSAR study on SGLT2 inhibitors, which shows that our 3D QSAR models are better than earlier models to predict good inhibitory activity. CoMFA and CoMSIA models generated in this work can provide useful information to design new compounds and helped in prediction of activity prior to synthesis.
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Qiao B, Foord ME, Wei MS, Stephens RB, Key MH, McLean H, Patel PK, Beg FN. Dynamics of high-energy proton beam acceleration and focusing from hemisphere-cone targets by high-intensity lasers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:013108. [PMID: 23410447 DOI: 10.1103/physreve.87.013108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Indexed: 06/01/2023]
Abstract
Acceleration and focusing of high-energy proton beams from fast-ignition (FI) -related hemisphere-cone assembled targets have been numerically studied by hybrid particle-in-cell simulations and compared with those from planar-foil and open-hemisphere targets. The whole physical process including the laser-plasma interaction has been self-consistently modeled for 15 ps, at which time the protons reach asymptotic motion. It is found that the achievable focus of proton beams is limited by the thermal pressure gradients in the co-moving hot electrons, which induce a transverse defocusing electric field that bends proton trajectories near the axis. For the advanced hemisphere-cone target, the flow of hot electrons along the cone wall induces a local transverse focusing sheath field, resulting in a clear enhancement in proton focusing; however, it leads to a significant loss of longitudinal sheath potential, reducing the total conversion efficiency from laser to protons.
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Ping Y, Kemp AJ, Divol L, Key MH, Patel PK, Akli KU, Beg FN, Chawla S, Chen CD, Freeman RR, Hey D, Higginson DP, Jarrott LC, Kemp GE, Link A, McLean HS, Sawada H, Stephens RB, Turnbull D, Westover B, Wilks SC. Dynamics of relativistic laser-plasma interaction on solid targets. PHYSICAL REVIEW LETTERS 2012; 109:145006. [PMID: 23083255 DOI: 10.1103/physrevlett.109.145006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Indexed: 06/01/2023]
Abstract
A novel time-resolved diagnostic is used to record the critical surface motion during picosecond-scale relativistic laser interaction with a solid target. Single-shot measurements of the specular light show a redshift decreasing with time during the interaction, corresponding to a slowing-down of the hole boring process into overdense plasma. On-shot full characterization of the laser pulse enables simulations of the experiment without any free parameters. Two-dimensional particle-in-cell simulations yield redshifts that agree with the data, and support a simple explanation of the slowing-down of the critical surface based on momentum conservation between ions and reflected laser light.
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Ma T, Izumi N, Tommasini R, Bradley DK, Bell P, Cerjan CJ, Dixit S, Döppner T, Jones O, Kline JL, Kyrala G, Landen OL, LePape S, Mackinnon AJ, Park HS, Patel PK, Prasad RR, Ralph J, Regan SP, Smalyuk VA, Springer PT, Suter L, Town RPJ, Weber SV, Glenzer SH. Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E115. [PMID: 23126937 DOI: 10.1063/1.4733313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.
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Mackinnon AJ, Kline JL, Dixit SN, Glenzer SH, Edwards MJ, Callahan DA, Meezan NB, Haan SW, Kilkenny JD, Döppner T, Farley DR, Moody JD, Ralph JE, MacGowan BJ, Landen OL, Robey HF, Boehly TR, Celliers PM, Eggert JH, Krauter K, Frieders G, Ross GF, Hicks DG, Olson RE, Weber SV, Spears BK, Salmonsen JD, Michel P, Divol L, Hammel B, Thomas CA, Clark DS, Jones OS, Springer PT, Cerjan CJ, Collins GW, Glebov VY, Knauer JP, Sangster C, Stoeckl C, McKenty P, McNaney JM, Leeper RJ, Ruiz CL, Cooper GW, Nelson AG, Chandler GGA, Hahn KD, Moran MJ, Schneider MB, Palmer NE, Bionta RM, Hartouni EP, LePape S, Patel PK, Izumi N, Tommasini R, Bond EJ, Caggiano JA, Hatarik R, Grim GP, Merrill FE, Fittinghoff DN, Guler N, Drury O, Wilson DC, Herrmann HW, Stoeffl W, Casey DT, Johnson MG, Frenje JA, Petrasso RD, Zylestra A, Rinderknecht H, Kalantar DH, Dzenitis JM, Di Nicola P, Eder DC, Courdin WH, Gururangan G, Burkhart SC, Friedrich S, Blueuel DL, Bernstein LA, Eckart MJ, Munro DH, Hatchett SP, Macphee AG, Edgell DH, Bradley DK, Bell PM, Glenn SM, Simanovskaia N, Barrios MA, Benedetti R, Kyrala GA, Town RPJ, Dewald EL, Milovich JL, Widmann K, Moore AS, LaCaille G, Regan SP, Suter LJ, Felker B, Ashabranner RC, Jackson MC, Prasad R, Richardson MJ, Kohut TR, Datte PS, Krauter GW, Klingman JJ, Burr RF, Land TA, Hermann MR, Latray DA, Saunders RL, Weaver S, Cohen SJ, Berzins L, Brass SG, Palma ES, Lowe-Webb RR, McHalle GN, Arnold PA, Lagin LJ, Marshall CD, Brunton GK, Mathisen DG, Wood RD, Cox JR, Ehrlich RB, Knittel KM, Bowers MW, Zacharias RA, Young BK, Holder JP, Kimbrough JR, Ma T, La Fortune KN, Widmayer CC, Shaw MJ, Erbert GV, Jancaitis KS, DiNicola JM, Orth C, Heestand G, Kirkwood R, Haynam C, Wegner PJ, Whitman PK, Hamza A, Dzenitis EG, Wallace RJ, Bhandarkar SD, Parham TG, Dylla-Spears R, Mapoles ER, Kozioziemski BJ, Sater JD, Walters CF, Haid BJ, Fair J, Nikroo A, Giraldez E, Moreno K, Vanwonterghem B, Kauffman RL, Batha S, Larson DW, Fortner RJ, Schneider DH, Lindl JD, Patterson RW, Atherton LJ, Moses EI. Assembly of high-areal-density deuterium-tritium fuel from indirectly driven cryogenic implosions. PHYSICAL REVIEW LETTERS 2012; 108:215005. [PMID: 23003274 DOI: 10.1103/physrevlett.108.215005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Indexed: 06/01/2023]
Abstract
The National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ~1.0±0.1 g cm(-2), which is 67% of the ignition requirement. These conditions were obtained using 192 laser beams with total energy of 1-1.6 MJ and peak power up to 420 TW to create a hohlraum drive with a shaped power profile, peaking at a soft x-ray radiation temperature of 275-300 eV. This pulse delivered a series of shocks that compressed a capsule containing cryogenic deuterium-tritium to a radius of 25-35 μm. Neutron images of the implosion were used to estimate a fuel density of 500-800 g cm(-3).
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Ma T, Sawada H, Patel PK, Chen CD, Divol L, Higginson DP, Kemp AJ, Key MH, Larson DJ, Le Pape S, Link A, MacPhee AG, McLean HS, Ping Y, Stephens RB, Wilks SC, Beg FN. Hot electron temperature and coupling efficiency scaling with prepulse for cone-guided fast ignition. PHYSICAL REVIEW LETTERS 2012; 108:115004. [PMID: 22540481 DOI: 10.1103/physrevlett.108.115004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Indexed: 05/31/2023]
Abstract
The effect of increasing prepulse energy levels on the energy spectrum and coupling into forward-going electrons is evaluated in a cone-guided fast-ignition relevant geometry using cone-wire targets irradiated with a high intensity (10(20) W/cm(2)) laser pulse. Hot electron temperature and flux are inferred from Kα images and yields using hybrid particle-in-cell simulations. A two-temperature distribution of hot electrons was required to fit the full profile, with the ratio of energy in a higher energy (MeV) component increasing with a larger prepulse. As prepulse energies were increased from 8 mJ to 1 J, overall coupling from laser to all hot electrons entering the wire was found to fall from 8.4% to 2.5% while coupling into only the 1-3 MeV electrons dropped from 0.57% to 0.03%.
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Gohil JT, Patel PK, Gupta P. Evaluation of oxidative stress and antioxidant defence in subjects of preeclampsia. J Obstet Gynaecol India 2012. [PMID: 23204680 DOI: 10.1007/s13224-011-0094-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Abstract
OBJECTIVES To evaluate the parameters of oxidative stress and anti oxidant defense in preeclampsia and thereby find any etiological correlation. METHODS Study was carried out on pregnant and non pregnant women attending or admitted in the Obstetrics and Gynecology Department of SSG Hospital, Baroda between 1st June 2007 to 31st May 2008. Each serum sample from different groups was evaluated for malondialdehyde (MDA), a product of lipid peroxidation process as a marker for oxidative stress and reduced Glutathione, Superoxide Dismutase, and Catalase for antioxidant enzyme activity and a comparison drawn and analyzed using t-test and χ(2) test. RESULTS The levels of MDA (a lipid peroxidation product) increased significantly in pregnancy compared to non-pregnant females and further significantly increased in preeclampsia compared to normal pregnant females. The superoxide dismutase levels, catalase levels and vit-E levels were found to be increased in preeclamptic females as compared to normal pregnant females. CONCLUSION Preeclampsia is found to be a condition with markedly increased oxidative stress as is evidenced by highly significantly increased levels of MDA, a marker of lipid peroxidation. Levels of antioxidant enzymes, viz. reduced glutathione, superoxide dismutase, catalase and vitamin E have been found to be increased in preeclampsia as compared to normal pregnant females. This may be a compensatory mechanism for handling the increased oxidative stress.
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Akli KU, Sanchez del Rio M, Jiang S, Storm MS, Krygier A, Stephens RB, Pereira NR, Baronova EO, Theobald W, Ping Y, McLean HS, Patel PK, Key MH, Freeman RR. A novel zirconium Kα imager for high energy density physics research. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:123503. [PMID: 22225215 DOI: 10.1063/1.3665931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the development and characterization of a zirconium Kα imager for high energy density physics research. The imager consists of a spherically bent quartz crystal operating at 15.7 keV photon energy. We compare the performance of the imager in terms of integrated reflectivity (R(int)) and temperature dependent collection efficiency (η(Te)) to that of the widely used Cu Kα imager. Our collisional-radiative simulations show that the new imager can be reliably used up to 250 eV plasma temperature. Monte Carlo simulations show that for a 25 μm thick tracer layer of zirconium, the contribution to Kα production from photo-pumping is only 2%. We present, for the first time, 2D spatially resolved images of zirconium plasmas generated by a high intensity short pulse laser interacting with Zr solid targets.
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