Analytic models of high-temperature hohlraums

Stygar, W. A.; Olson, R. E.; Spielman, R. B.; Leeper, R. J.

doi:10.1103/physreve.64.026410

Cited by 34 publications

(67 citation statements)

References 104 publications

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“…Equations (3) and (4) assume that the minimum value of the initial stack-MITL inductance L s required for reliable accelerator operation is approximately given by the following empirical relation [42]:…”

Section: B Analytic Model Of a Marx-based Acceleratormentioning

confidence: 99%

“…We assume that the desired peak pinch current, pinch implosion time, pinch length, and initial pinch radius are given by I, i , ', and R, respectively. These parameters determine the requisite value of the pinch mass m, which is approximately given by the following expression [40,42]:…”

Section: B Analytic Model Of a Marx-based Acceleratormentioning

confidence: 99%

“…Recent calculations suggest that accelerators with electrical powers in excess of 1000 TW would be required to drive z-pinch implosions that radiate in excess of 1000 TW of x-ray power [42]. Such radiated powers would enable large-diameter ICF-capsule-implosion experiments [42 -61] and other high-energy-density-physics experiments [62 -68] to be conducted over heretofore inaccessible parameter regimes.…”

Section: Introductionmentioning

confidence: 99%

“…Z delivers 55 TW of electrical power to the accelerator's vacuum-insulator stack, and 19 MA to a 10-mm-initial-radius 10-mm-length pinch that implodes in 95 ns [33][34][35][36][37][38][39][40][41][42][43]. Such a pinch radiates 130 TW of x-ray power in a 12-ns pulse [33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

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Architecture of petawatt-classz-pinch accelerators

Stygar

Cuneo

Headley³

et al. 2007

Phys. Rev. ST Accel. Beams

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211

128

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We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow ( 1 s) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses ( 1 s) required to drive z pinches. The other is powered by linear transformer drivers (LTDs), which are less mature but produce much shorter pulses than conventional Marxes. Consequently, an LTD-driven accelerator promises to be (at a given pinch current and implosion time) more efficient and reliable. The Marx-driven accelerator produces a peak electrical power of 500 TW and includes the following components: (i) 300 Marx generators that comprise a total of 1:8 10 4 capacitors, store 98 MJ, and erect to 5 MV; (ii) 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii) 600 5-MV laser-triggered gas switches; (iv) three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v) a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi) six magnetically insulated vacuum transmission lines (MITLs); and (vii) a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210 LTD modules that include a total of 1 10 6 capacitors and 5 10 5 200-kV electrically triggered gas switches. The LTD accelerator stores 182 MJ and produces a peak electrical power of 1000 TW. The accelerator delivers an effective peak current of 68 MA to a pinch that implodes in 95 ns, and 75 MA to a pinch that implodes in 120 ns. Conceptually straightforward upgrades to these designs would deliver even higher pinch currents and faster implosions.

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Section: B Analytic Model Of a Marx-based Acceleratormentioning

confidence: 99%

Section: B Analytic Model Of a Marx-based Acceleratormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Architecture of petawatt-classz-pinch accelerators

Stygar

Cuneo

Headley³

et al. 2007

Phys. Rev. ST Accel. Beams

Self Cite

211

128

View full text Add to dashboard Cite

show abstract

“…In various hohlraum experiments, some type of sample, or other package, is placed at the hohlraum midplane, to expose it to the radiation drive. Historically, hohlraum radiation conditions have also been diagnosed from midplane wall reemission flux [7][8][9], which is equal to the midplane wall incident radiation multiplied by the albedo. Clearly, hohlraum radiation diagnostic results will vary depending on the location of the wall reemission they sample.…”

Section: Figmentioning

confidence: 99%

Numerical modeling of Hohlraum radiation conditions: Spatial and spectral variations due to sample position, beam pointing, and Hohlraum geometry

2005

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View-factor simulations are presented of the spatially varying radiation conditions inside double-ended gold hohlraums and single-ended gold hohlraums ("halfraums") used in inertial confinement fusion (ICF) and high energy density (HED) physics experiments [J. Lindl, Phys. Plasmas 11, 339 (2004); M. D. Rosen, Phys. Plasmas 3, 1803(1996]. It is shown that in many circumstances, the common assumption that the hohlraum "drive" can be characterized by a single temperature is too simplistic. Specifically, the radiation conditions seen by an experimental package can differ significantly from the wall reemission measured through diagnostic holes or laser entrance holes (LEHs) by absolutely calibrated detectors. Furthermore, even in situations where the radiation temperature is roughly the same for diagnostics and experimental packages, or for packages at different locations, the spectral energy distributions can vary significantly, due to the differing fractions of reemitting wall, laser hot spots, and LEHs seen from different locations. We find that the spatial variation of temperature, and especially the differences between what diagnostics looking in the LEH measure vs. the radiation temperature on wall-mounted experimental packages, is generally greater for double-ended hohlraums than it is for halfraums. View-factor simulations can also be used to explore experimental variables (halfraum length and geometry, sample position, and beam pointing) that can be adjusted in order to, for example, maximize the radiation flux onto a sample, or other package. In this vein, simulations of hohlraums and halfraums with LEH shields are also presented.

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The physics of radiation transport in dense plasmas

et al. 2002

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Radiation transport redistributes energy within a medium through the emission and reabsorption of photons. These processes also have a pronounced effect on the spectrum of radiation that escapes the medium. As the deliverable energies of plasma drivers such as lasers and pulsed-power generators steadily increase, denser and/or more massive plasmas can be created. Such plasmas are more absorptive to their own emitted radiation, with portions of the line spectrum frequently being highly opaque. Thus, radiation transport becomes more important, along with the need to consider its impact on the design of experiments and their diagnosis. This tutorial paper covers the basic theory and equations describing radiation transport, its physical effects, experimental examples of transport phenomena, and current challenges and issues. Among the specific topics discussed are requirements for local thermodynamic equilibrium (LTE), conditions for diffusion and the use of the diffusion approximation, the formation of emission and absorption lines, the approach of an emitted spectrum to the Planck limit, and diagnostic applications of transport effects.

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Analytic models of high-temperature hohlraums

Abstract: .A unified set of high-temperature-hohlraum models has been developed. hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented.

Cited by 34 publications

References 104 publications

Architecture of petawatt-classz-pinch accelerators

Architecture of petawatt-classz-pinch accelerators

Numerical modeling of Hohlraum radiation conditions: Spatial and spectral variations due to sample position, beam pointing, and Hohlraum geometry

The physics of radiation transport in dense plasmas

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