A novel method for determining the M-band fraction in laser-driven gold hohlraums

Li, Yongsheng; Huo, Wen Yi; Lan, Ke

doi:10.1063/1.3551698

Cited by 30 publications

(13 citation statements)

References 17 publications

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“…We note that although the uncertainties in EOS and opacity models may play a significant role on determining the exact HI amplitude and/or growing factor, the major conclusions of us on the impact of x-ray spectral distribution on implosion performance could not be altered with the use of different opacity or EOS models. The RDMG code has been well tested by the many ablation and implosion experimental results, 26,27 and that confirms the reliability of RDMG in the simulation research of ignition capsule implosion.…”

Section: Model Descriptionsupporting

confidence: 64%

Sensitivity study of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum

Zou

et al. 2012

Physics of Plasmas

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The paper investigates theoretically the sensitivities of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum. In the simulation, the hohlraum radiation is represented by a Planckian spectrum for the main drive plus a gaussian bump centered at energy Ec for preheating x-rays. Simulation results show that with the increasing of center energy Ec, the Atwood number at the fuel-ablator interface increases rapidly due to the preheating and expanding of the inner undoped CH layer. The growing of Atwood number indicates the hydrodynamic instability (HI) growth and mixing at this interface. On the other hand, the increasing of Ec results in a large density gradient scale length of ablation front and stabilizes the HI growth at ablation front. The changes of the hard x-ray spectrum have significant influences on other important implosion parameters including the ablator mass remaining, shock timing, implosion velocity, and yield as well. High-precision results on the hard x-ray spectral distribution of hohlraum are thus critical for optimizing the ignition capsule design to limit the HI growth.

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Section: Model Descriptionsupporting

confidence: 64%

Sensitivity study of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum

Zou

et al. 2012

Physics of Plasmas

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“…When the M-band flux in the radiation source is obviously higher than the amount in the Planckian spectrum, the shock velocity in a witness material depends not only on T R , but also on f M . According to our studies, the variations of the opacity with frequency in Al and Ti are quite different [13]. For Al, the opacity is low in the regions of the O band (n ¼ 5 of Au, radiations at about 450 eV) and N band (n ¼ 4 of Au, radiations about 800 eV) but high in the M-band region.…”

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confidence: 86%

“…With this detailed thickness information and the breakout time interval provided by the step images of SOP, we can obtain an averaged shock velocity. However, this shock velocity is merely a nominal velocity since the movement of the exterior surfaces of witness plates due to the preheat effect [3,13,16] cannot be detected by SOP. Hence, we perform a post-experiment calculation and compare the measured breakout time intervals with the calculated results under radiation sources with various groups of (T R , f M ).…”

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confidence: 95%

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Determination of the HohlraumM-band Fraction by a Shock-Wave Technique on the SGIII-Prototype Laser Facility

Huo¹,

Lan²,

Li³

et al. 2012

Phys. Rev. Lett.

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The proposal of simultaneously determining the hohlraum peak radiation temperature T(R) and M-band fraction f(M) by shock velocity measurement technique [Y. S. Li et al. Phys. Plasmas 18, 022701 (2011)] is demonstrated for the first time in recent experiments conducted on SGIII-prototype laser facility. In the experiments, T(R) and f(M) are determined by using the observed shock velocities in Al and Ti. For the Au hohlraum used in the experiments, T(R) is about 160 eV and f(M) is around 4.3% under a 1 ns laser pulse of 2 kJ. The results from this method are complementary to those from the broadband x-ray spectrometer, and the technique can be further used to determine T(R) and f(M) inside an ignition hohlraum.

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“…When the M-band flux in a radiation source is obviously higher than the amount in the Planckian spectrum, V s in a witness material depends not only on T R , but also on f M . We had developed a method for determining T R and f M inside hohlraums by using a shock wave technique 31,32 and had successfully applied in determining T R and f M of hohlraums driven by 2 kJ laser. In this article, we will present our new experimental results obtained by using this technique at a higher laser energy of 6 kJ.…”

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confidence: 99%

The radiation temperature andM-band fraction inside hohlraum on the SGIII-prototype laser facility

Huo¹,

Yang²,

Lan³

et al. 2014

Physics of Plasmas

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The radiation temperature T R and M-band fraction f M inside the vacuum Au hohlraum have been experimentally determined by a shock wave technique and a broadband soft x-ray spectrometer (SXS) on the SGIII-prototype laser facility. From the results of the shock wave technique, T R is about 202 eV, and f M is about 9% for the hohlraums driven by a 1 ns flattop pulse of 6 kJ laser energy. The Continuous Phase Plate (CPP) for beam smoothing is applied in the experiment, which increases T R to 207 eV while has almost no influence on f M . Comparisons between the results from the two kinds of technologies show that T R from the shock wave technique is lower than that from SXS whether with CPP or not. However, f M from the shock wave technique is consistent with that from SXS without CPP, but obviously lower than the SXS's result with CPP. The preheat effect on exterior surface of witness plate is reduced by thicker thickness of witness plate designed for higher laser driven energy. V C 2014 AIP Publishing LLC. [http://dx.

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A novel method for determining the M-band fraction in laser-driven gold hohlraums

Cited by 30 publications

References 17 publications

Sensitivity study of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum

Sensitivity study of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum

Determination of the HohlraumM-band Fraction by a Shock-Wave Technique on the SGIII-Prototype Laser Facility

The radiation temperature andM-band fraction inside hohlraum on the SGIII-prototype laser facility

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