Magnetoimplosive Generators

Sakharov, A. D.

doi:10.1070/pu1966v009n02abeh002876

Cited by 222 publications

(238 citation statements)

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“…The first convincing evidence of the cosmic accel-eration was from the observation of supernovae, soon followed by the measurement of degree-scale cosmic microwave background (CMB) anisotropies (Hinshaw et al 2013;Planck Collaboration et al 2014, 2015a, and later by data on the baryon acoustic oscillation (BAO) at lower redshifts (Sakharov 1966;Peebles & Yu 1970;Sunyaev & Zeldovich 1970;Blake & Glazebrook 2003;Seo & Eisenstein 2003). We combine the latest versions of these measurements with that of the local Hubble constant H 0 (Riess et al 2016).…”

Section: Introductionmentioning

confidence: 99%

An Evaluation of Cosmological Models from the Expansion and Growth of Structure Measurements

Zhai

Blanton

Slosar

et al. 2017

ApJ

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We compare a large suite of theoretical cosmological models to observational data from the cosmic microwave background, baryon acoustic oscillation measurements of expansion, Type Ia SNe measurements of expansion, redshift space distortion measurements of the growth of structure, and the local Hubble constant. Our theoretical models include parametrizations of dark energy as well as physical models of dark energy and modified gravity. We determine the constraints on the model parameters, incorporating the redshift space distortion data directly in the analysis. To determine whether models can be ruled out, we evaluate the p-value (the probability under the model of obtaining data as bad or worse than the observed data). In our comparison, we find the well known tension of H 0 with the other data; no model resolves this tension successfully. Among the models we consider, the large scale growth of structure data does not affect the modified gravity models as a category particularly differently than dark energy models; it matters for some modified gravity models but not others, and the same is true for dark energy models. We compute predicted observables for each model under current observational constraints, and identify models for which future observational constraints will be particularly informative.

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Section: Introductionmentioning

confidence: 99%

An Evaluation of Cosmological Models from the Expansion and Growth of Structure Measurements

Zhai

Blanton

Slosar

et al. 2017

ApJ

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“…While we do not yet have any definite quantum gravity allowing us to understand the inside of the black hole and resolve it separately, we must turn our attention to regular models, which are motivated by quantum arguments. The earliest idea, in mid-1960s, due to Sakharov [5] and Gliner [6], suggests that singularities could be avoided by matter, i.e., with a de Sitter core, with the equation of state p = −ρ. This equation of state is obeyed by the cosmological vacuum and hence, T μν takes on a false vacuum of the form T μν = g μν ; is the cosmological constant.…”

Section: Introductionmentioning

confidence: 99%

Horizon structure of rotating Bardeen black hole and particle acceleration

Ghosh

Amir

2015

Eur. Phys. J. C

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We investigate the horizon structure and ergosphere in a rotating Bardeen regular black hole, which has an additional parameter (g) due to the magnetic charge, apart from the mass (M) and the rotation parameter (a). Interestingly, for each value of the parameter g, there exists a critical rotation parameter (a = a E ), which corresponds to an extremal black hole with degenerate horizons, while for a < a E it describes a non-extremal black hole with two horizons, and no black hole for a > a E . We find that the extremal value a E is also influenced by the parameter g, and so is the ergosphere. While the value of a E remarkably decreases when compared with the Kerr black hole, the ergosphere becomes thicker with the increase in g. We also study the collision of two equal mass particles near the horizon of this black hole, and explicitly show the effect of the parameter g. The center-of-mass energy (E CM ) not only depend on the rotation parameter a, but also on the parameter g. It is demonstrated that the E CM could be arbitrarily high in the extremal cases when one of the colliding particles has a critical angular momentum, thereby suggesting that the rotating Bardeen regular black hole can act as a particle accelerator.

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“…[5]) and the external fields that can be generated by coils. Magnetic-flux compression [6] is a viable path to generating tens of MG magnetic fields with adequate size compression of a metal liner driven by high explosives [7,8] or by pulsed power. The latter approach has been pursued by the Z-pinch [9] communities.…”

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confidence: 99%

Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas

et al. 2009

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The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] was used to implode cylindrical CH targets filled with deuterium gas and seeded with a strong external field (>50 kG) from a specially developed magnetic pulse generator. This seed field was trapped (frozen) in the shock-heated gas fill and compressed by the imploding shell at a high implosion velocity, minimizing the effect of resistive flux diffusion. The magnetic fields in the compressed core were probed via proton deflectrometry using the fusion products from an imploding D 3 He target. Line-averaged magnetic fields between 30 and 40 MG were observed. In the magnetic fusion energy (MFE) concept, a strong magnetic field confines the plasma and reduces the electron thermal conduction to the vessel wall [1]. The magnetic pressure of typical $0:1-MG fields is higher than the total energy density of the plasma (with ¼ 2 0 p=B 2 < 1). MFE plasmas are fully magnetized and characterized by a Hall parameter ! ce > 1 since the modest gyrofrequency ! ce is matched by long collision times . In contrast, typical inertial confinement fusion (ICF) plasmas have collision frequencies higher by 10 to 12 orders of magnitude because of their extreme density. In such systems, thermal conduction losses are a major factor in the energy balance of an implosion. While it can be more difficult, magnetizing the hot spot in ICF implosions can lead to improved gains and to a reduction of the energy required for ignition. A similar approach is used in the magnetized target fusion concept [2], where the fusion burn requires relatively low-implosion velocities, provided there is an adequate magnetic thermal insulation. In ICF implosions, lower implosion velocities lead to higher gains [3]. However, tens of MG are needed to achieve ! ce $ 1 in the hot spot of a typical, direct drive DT ignition target [4] with hot-spot density of $30 g=cc and a temperature of $7 keV. Such a field is higher than both the self-generated magnetic fields (see Ref. [5]) and the external fields that can be generated by coils. Magnetic-flux compression [6] is a viable path to generating tens of MG magnetic fields with adequate size compression of a metal liner driven by high explosives [7,8] or by pulsed power. The latter approach has been pursued by the Z-pinch [9] communities. The results from the first experiments on a new approach that provides very effective flux compression are reported here. The field is compressed by the ablative pressure exerted on an imploding ICF capsule by the driving laser [10]. This approach was proposed in the 1980s [11] as a way to achieve record compressed fields with possible applications for fusion [12] but no laser experiments were performed. There are numerous advantages to this approach as the implosion velocity is high (a few 10 7 cm=s) and the hot plasma is an effective conductor that tra...

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Magnetoimplosive Generators

Cited by 222 publications

References 0 publications

An Evaluation of Cosmological Models from the Expansion and Growth of Structure Measurements

An Evaluation of Cosmological Models from the Expansion and Growth of Structure Measurements

Horizon structure of rotating Bardeen black hole and particle acceleration

Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas

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