Verification of fast heating of core plasmas produced by counter-illumination of implosion lasers

Miura, Eisuke; Mori, Yoshitaka; Ishii, Katsuhiro; Sakata, Shohei; Abe, Yuki; Arikawa, Yasunobu; Nakajima, N.; Takizawa, Ryunosuke; Morita, Hiroki; Matsuo, Kazuki; Mirfayzi, S. R.; Sunahara, A.; Ozaki, T.; Iwamoto, A.; Komeda, Osamu; Hanayama, Ryohei; Okihara, S.; Sentoku, Y.; Fujioka, Shinsuke; Sakagami, Hiroyuki; Johzaki, Tomoyuki; Kitagawa, Yoneyoshi

doi:10.1016/j.hedp.2020.100890

Cited by 4 publications

(8 citation statements)

References 17 publications

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“…In this case the shell is mainly compressed in the y direction, and the core resembles a sausage. The difference in the timing in figures 3(a) and (b) was due to the difference in their laser configurations, as described in [12]. The simulation postulates for the transverse mode that T e ∼ 600 eV, ρ ∼ 3 g cm −3 , and Yn = 4.2 × 10 5 /4π sr.…”

Section: Star-2d-ale Simulation Of the Counter Implosionmentioning

confidence: 98%

“…The two-dimensional hydrocode 'STAR 2D arbitrary Lagrangean-Eulerian code (STAR-2D-ALE)' was developed to simulate axial and transverse implosions by counter beams propagated from GXII [12]. Figure 3(a) shows the x-ray emission for the axial mode at 2.83 ns, which was the maximum compression timing, +330 ps after the GXII peak resulting in an electron temperature (T e ) of ∼800 eV, mass density (ρ) of ∼2 g cm −3 and a thermal DD neutron yield (Yn) equal to 2.63 × 10 5 /4π sr.…”

Section: Star-2d-ale Simulation Of the Counter Implosionmentioning

confidence: 99%

“…Figure 4(c) shows that the peak of the GXII laser is at 1.79 ns and the x-ray emission peak is at 2.0 ns. The delay The temporal resolution of the streak camera was 40 ps, but its shot-by-shot jitter was 100 ps [12]. is the shot number.…”

Section: X-ray Emission From the Imploded Corementioning

confidence: 99%

“…The vertical axis is not a length l, but a ρl [18]. The experimental point of ρR is between the two curves, i.e., the core [12]. (e) Rosseland and Planck absorption mean-free-paths as functions of T e .…”

Section: X-ray Emission For the Axial Modementioning

confidence: 99%

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Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

et al. 2022

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This study investigates the efficiency of the fast heating when a preimploded core is directly heated with an ultraintense laser(a heating laser). The efficiency is defined as an increment of internal core energy divided by heating laser energy on target. Six counterbeams from the GEKKO XII (GXII) green laser at the Institute of Laser Engineering (ILE), Osaka University, of which the output was 1.6kJ, imploded a spherical CD (Deuterated polystyrene) shell target and formed a dense core. DD-reacted protons and the x-ray core emissions showed a core density of 2.8 ∼ 2.7g/cm3. DD-reacted thermal neutrons were used to estimate the core temperature determined as 650 ∼ 750 eV. The core was then directly heated by a laser for fast-ignition experiments (LFEX), an extremely energetic ultrashort pulse laser at the ILE either with its axis lying to the GXII bundle axis, or with its axis perpendicular to the GXII bundle axis. We call the former laser configuration “Axial mode”, and the latter “Transverse mode”. η is 2% or less for Axial mode and 6% or less for Transverse mode. The efficiencies were compared to that of a uniform implosion mode, which was 3%.

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Section: Star-2d-ale Simulation Of the Counter Implosionmentioning

confidence: 98%

Section: Star-2d-ale Simulation Of the Counter Implosionmentioning

confidence: 99%

Section: X-ray Emission From the Imploded Corementioning

confidence: 99%

Section: X-ray Emission For the Axial Modementioning

confidence: 99%

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Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

et al. 2022

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“…The focal intensity was 5 × 10 18 W cm −2 , evaluated from the focal spot diameter of 70 μm FWHM measured from an CW alignment laser, resulting in a normalized field amplitude a 0 of 2.0. The diagnostics comprised an x-ray pinhole camera [41] and x-ray spectrometer utilizing highly oriented pyrolytic graphite (HOPG) as a diffractor for the x-ray detection [42] and a multichannel time-of-flight neutron spectrometer (MANDALA) for neutron detection [43]. Figure 7(b) shows the x-ray pinhole image on the target surface.…”

Section: Demonstration Of Laser Irradiation On the Cu-dma Thin Film T...mentioning

confidence: 99%

Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments

et al. 2022

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In high energy density physics including inertial fusion energy using high power laser, doping tracer atoms and deuteration of target materials play an important role in diagnosis. For example, the low concentration copper dopant acts as an X-ray source for electron temperature detection while the deuterium dopant acts as a neutron source for fusion reaction detection. However, the simultaneous achievement of Cu doping, deuterated polymer, mechanical toughness and chemical robustness for the fabrication process is not so simple. In this study, we report the successful fabrication of a Cu-doped deuterated target. The obtained samples were characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The simultaneous measurements of Cu K-shell X-ray emission and beam fusion neutron were demonstrated using a petawatt laser in Osaka university.

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Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

et al. 2023

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Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition.

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Verification of fast heating of core plasmas produced by counter-illumination of implosion lasers

Cited by 4 publications

References 17 publications

Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments

Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

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