The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform
Kazuyuki Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Energetics and dynamics of laser-assisted field evaporation: Time-dependent density functional theory simulations
Physical Review B, 2015Co-Authors: E.p. Silaeva, Kazuki Uchida, Yasumitsu Suzuki, Kazuyuki WatanabeAbstract:High positive electrostatic (dc) field can break the bonds in molecules and strip away Atoms from the solid surfaces. The dynamics of this field evaporation under laser pulse is studied for a ${\mathrm{H}}_{2}$ molecule and a ${\mathrm{Si}}_{4}$ cluster using time-dependent density functional theory combined with molecular dynamics. This allows us to monitor the position and charge state of the Evaporated Atom in real time. Our simulations demonstrate that the critical dc field for the evaporation is lower if the molecule/cluster is illuminated by a laser pulse. The behavior of the evaporation threshold as a function of laser intensity and dc field is in qualitative agreement with experiments and provides important insights into the mechanisms of laser-assisted field evaporation. Additionally, the laser-assisted field evaporation is found to be sensitive to the laser energy according to the photoabsorption spectra that demonstrate a pronounced redshift in the lower energy region at higher dc field values.
K.n. Ulyanov - One of the best experts on this subject based on the ideXlab platform.
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Peculiarities of the slow ion flow movement in the near-anode region of a high-current vacuum arc
IEEE Transactions on Plasma Science, 2001Co-Authors: J.i. Londer, K.n. UlyanovAbstract:A one-dimensional model of the quasi-stationary vacuum arc is considered in terms of a four-flow hydrodynamics approximation. The presented model allows calculating kinetics of Evaporated Atom volume ionization and distribution of the main parameters characterizing each flow over the interelectrode gap.
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Peculiarities of the slow ion flow movement in the near-anode region of a high-current vacuum arc
Proceedings ISDEIV. 19th International Symposium on Discharges and Electrical Insulation in Vacuum (Cat. No.00CH37041), 1Co-Authors: J.i. Londer, K.n. UlyanovAbstract:The purpose of the present work is to study the structure of the near-anode region of a high-current vacuum arc on the basis of a generalized mathematical model including the electron energy balance equation and continuity equations for Atoms and slow ions, that allow for the processes of slow ion generation and Atom disappearance due to electron ionization. The presented model allows to calculate kinetics of Evaporated Atom volume ionization and distribution of the main parameters characterizing each flow over the interelectrode gap.
E.p. Silaeva - One of the best experts on this subject based on the ideXlab platform.
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Energetics and dynamics of laser-assisted field evaporation: Time-dependent density functional theory simulations
Physical Review B, 2015Co-Authors: E.p. Silaeva, Kazuki Uchida, Yasumitsu Suzuki, Kazuyuki WatanabeAbstract:High positive electrostatic (dc) field can break the bonds in molecules and strip away Atoms from the solid surfaces. The dynamics of this field evaporation under laser pulse is studied for a ${\mathrm{H}}_{2}$ molecule and a ${\mathrm{Si}}_{4}$ cluster using time-dependent density functional theory combined with molecular dynamics. This allows us to monitor the position and charge state of the Evaporated Atom in real time. Our simulations demonstrate that the critical dc field for the evaporation is lower if the molecule/cluster is illuminated by a laser pulse. The behavior of the evaporation threshold as a function of laser intensity and dc field is in qualitative agreement with experiments and provides important insights into the mechanisms of laser-assisted field evaporation. Additionally, the laser-assisted field evaporation is found to be sensitive to the laser energy according to the photoabsorption spectra that demonstrate a pronounced redshift in the lower energy region at higher dc field values.
J.i. Londer - One of the best experts on this subject based on the ideXlab platform.
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Peculiarities of the slow ion flow movement in the near-anode region of a high-current vacuum arc
IEEE Transactions on Plasma Science, 2001Co-Authors: J.i. Londer, K.n. UlyanovAbstract:A one-dimensional model of the quasi-stationary vacuum arc is considered in terms of a four-flow hydrodynamics approximation. The presented model allows calculating kinetics of Evaporated Atom volume ionization and distribution of the main parameters characterizing each flow over the interelectrode gap.
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Peculiarities of the slow ion flow movement in the near-anode region of a high-current vacuum arc
Proceedings ISDEIV. 19th International Symposium on Discharges and Electrical Insulation in Vacuum (Cat. No.00CH37041), 1Co-Authors: J.i. Londer, K.n. UlyanovAbstract:The purpose of the present work is to study the structure of the near-anode region of a high-current vacuum arc on the basis of a generalized mathematical model including the electron energy balance equation and continuity equations for Atoms and slow ions, that allow for the processes of slow ion generation and Atom disappearance due to electron ionization. The presented model allows to calculate kinetics of Evaporated Atom volume ionization and distribution of the main parameters characterizing each flow over the interelectrode gap.
Valerian Nemchinsky - One of the best experts on this subject based on the ideXlab platform.
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Cathode erosion in a high-pressure high-current arc: calculations for tungsten cathode in a free-burning argon arc
Journal of Physics D: Applied Physics, 2012Co-Authors: Valerian NemchinskyAbstract:The motion of an Evaporated Atom of the cathode material in a near-cathode plasma is considered. It is shown that the Evaporated Atom is ionized almost instantly. The created ion, under the influence of a strong electric field existing in the cathode proximity, has a high probability of returning to the cathode. A small fraction of Evaporated Atoms are able to diffuse away from the cathode to the region where they are involved in plasma flow and lose their chance to return to the cathode. The fraction of the total Evaporated Atoms, which do not return to the cathode, the escape factor, determines the net erosion rate. In order to calculate this factor, the distributions of the plasma parameters in the near-cathode plasma were considered. Calculations showed that the escape factor is on the order of a few per cent. Using experimental data on the plasma and cathode temperatures, we calculated the net erosion rate for a free-burning 200 A argon arc with a thoriated tungsten cathode. The calculated erosion rate is close to 1 µg s−1, which is in agreement with available experimental data.