WorldCat Identities

Metzler, Nathan

Works: 4 works in 4 publications in 2 languages and 6 library holdings
Classifications: QC476.2 M939 NO. 48,
Publication Timeline
Publications about  Nathan Metzler Publications about Nathan Metzler
Publications by  Nathan Metzler Publications by Nathan Metzler
Most widely held works by Nathan Metzler
Target design for heavy ion beam fusion by Jürgen Meyer-ter-Vehn ( Book )
1 edition published in 1981 in German and held by 3 WorldCat member libraries worldwide
Laser Imprint Reduction with a Short Shaping Laser Pulse Incident Upon a Foam-Plastic Target ( )
1 edition published in 2002 in English and held by 1 WorldCat member library worldwide
In the previous work [Metzler et al., Phys. Plasmas 6, 3283 "1999"] it was shown that a tailored density profile could be very effective in smoothing out the laser beam non-uniformities imprinted into a laser-accelerated target. However, a target with a smoothly graded density is difficult to manufacture. A method of dynamically producing a graded density profile with a short shaping laser pulse irradiating a foam layer on top of the payload prior to the drive pulse is proposed. It is demonstrated that the intensity and the duration of the shaping pulse, the time interval between the shaping pulse and the drive pulse, and the density ratio between the foam and the payload can be selected so that the laser imprint of the drive pulse is considerably suppressed without increasing the entropy of the payload. The use of the foam-plastic target and a shaping pulse reduces the imprinted mass perturbation amplitude by more than an order of magnitude compared to a solid plastic target. The requirements to the smoothing of the drive and shaping laser beams and to the surface finish of the foam-plastic sandwich target are discussed
Feedout and Richtmyer-Meshkov Instability at Large Density Difference ( )
1 edition published in 2001 in English and held by 1 WorldCat member library worldwide
The feedout process transfers mass perturbations from the rear to the front surface of a driven target, producing the seed for the Rayleigh-Taylor (RT) instability growth. The feedout mechanism is investigated analytically and numerically for the case of perturbation wavelength comparable to or less than the shock-compressed target thickness. The lateral mass flow in the target leads to oscillations of the initial mass non-uniformity before the reflected rippled rarefaction wave breaks out, which may result in RT bubbles produced at locations where the areal mass was initially higher. This process is determined by the evolution of hydrodynamic perturbations in the rippled rarefaction wave, which is not the same as the Richtmyer-Meshkov (RM) interfacial instability. An exact analytical formula is derived for the time-dependent mass variation in a rippled rarefaction wave, and explicit estimates are given for the time of first phase reversal and frequency of the oscillations. The limiting transition from the case of RM perturbation growth at large density difference "low ambient density behind the rear surface" to the case of feedout "zero density" is studied, and it is shown that the latter limit is approached only if the ambient density is extremely low, less than 1/1000 of the pre-shock target density
Reduction of Early-Time Perturbation Growth in Ablatively Driven Laser Targets Using Tailored Density Profiles ( )
1 edition published in 1999 in English and held by 1 WorldCat member library worldwide
We investigate analytically and numerically the effects of tailoring the density profile in a laser target in order to decrease imprinting of mass perturbations due to the long-wavelength modes. Inverting the acceleration of the ablation front during the shock transit time could reduce the early-time mass perturbation amplitudes developed in the target after the shock transit. This principle was first suggested for mitigating the RT instability of imploding Z-pinches [Velikovich et al., Phys. Rev. Lett. 77, 853 (1996); Phys. Plasmas 5, 3377 (1998)]. As the shock wave slows down propagating into higher density layers, the effective gravity near the ablation front has the same direction as the density gradient. This makes the mass perturbations near it oscillate at a higher frequency and at a lower amplitude than they normally would due to the "rocket effect" caused by mass ablation [Sanz, Phys. Rev. Lett. 73, 2700 (1994); Piriz et al., Phys. Plasmas 4, 1117 (1997)]. So, tailoring density profiles instead of using flat densities is demonstrated to reduce the "seed" mass perturbation amplitude at the onset of the exponential RT growth
Audience Level
Audience Level
  Kids General Special  
Audience level: 0.41 (from 0.00 for Laser Impr ... to 0.81 for Target des ...)
English (3)
German (1)