2,576 research outputs found

    Origin of nanosized diamonds in interstellar space and low-pressure-temperature Earth rocks

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    Nanosized diamond particles in the interstellar space and in the Earth rocks related with water presence. In the paper proposed the model of the nanosized diamond particle formation from oxidized water-carbon dioxide gaseous mixtures

    Metastable Nanosized Diamond Formation from Fluid Systems

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    The model of nanosized diamond particles formation at metastable P-T parameters from fluid is presented. It explains the specific of CVD diamond synthesis gases mixtures and hydrothermal growth of diamond at low P-T parameters as well as it explains the geneses of metamorphic and magmatic nano- and microdiamond in the shallow depth Earth rocks and the genesis of interstellar nanodiamond formations in the space

    Ion Species Stratification Within Strong Shocks in Two-Ion Plasmas

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    Strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al.{\it et \ al.}, PRE 96{\bf 96}, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by Mach number, MM. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification, and temperature separation). These are important effects, since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likely contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with arbitrary Mach number and relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Additionally, we find that the shock fronts are enriched with the lighter ion species, and the enrichment scales as M4M^4 for M1M \gg 1.Comment: 12 pages, 19 figures; submitted to Physics of Plasma
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