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A radial inhomogeneous magnetic field produced by counter-propagating currents in anti-Helmholtz configuration coils has been superimposed to a Penning trap. The confinement properties of electrons in such a trap have been studied...
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A radial inhomogeneous magnetic field produced by counter-propagating currents in anti-Helmholtz configuration coils has been superimposed to a Penning trap. The confinement properties of electrons in such a trap have been studied experimentally. Without the radial B-field we find a number of operating conditions where instabilities occur, arising from higher order contributions to the quadrupolar trapping field. When we apply the radial field the trap properties remain essentially unchanged until the strength of this field at the boundary of the electron cloud is of the same order as the homogeneous Penning field. Then a sudden breakdown in the confinement appears. The experiments have been performed in low magnetic fields. The equations of motions of the trapped particles can be cast in a dimensionless form and our results can be considered as independent of the field strength.
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摘要 :
A radial inhomogeneous magnetic field produced by counter-propagating currents in anti-Helmholtz configuration coils has been superimposed to a Penning trap. The confinement properties of electrons in such a trap have been studied...
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A radial inhomogeneous magnetic field produced by counter-propagating currents in anti-Helmholtz configuration coils has been superimposed to a Penning trap. The confinement properties of electrons in such a trap have been studied experimentally. Without the radial B-field we find a number of operating conditions where instabilities occur, arising from higher order contributions to the quadrupolar trapping field. When we apply the radial field the trap properties remain essentially unchanged until the strength of this field at the boundary of the electron cloud is of the same order as the homogeneous Penning field. Then a sudden breakdown in the confinement appears. The experiments have been performed in low magnetic fields. The equations of motions of the trapped particles can be cast in a dimensionless form and our results can be considered as independent of the field strength.
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We derived a Schamel-Burgers equation to study the dynamics of nonlinear structures in dissipative electronegative plasma having Boltzmann negative ions and kappa-distributed trapped electrons. A recently introduced Tangent hyperb...
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We derived a Schamel-Burgers equation to study the dynamics of nonlinear structures in dissipative electronegative plasma having Boltzmann negative ions and kappa-distributed trapped electrons. A recently introduced Tangent hyperbolic method has been employed to get the solutions of the differential equations which contain fractional nonlinearity. The effects of different physical parameters particularly, the kinematic viscosity, the superthermality, the trapping efficiency and the electronegativity factor on the ion acoustic (IA) shock profiles have been elaborated. In case of non-dissipative electronegative plasma, the small amplitude double layers (DLs) have also been investigated. It has been elaborated that the DLs strongly depend on the system parameters. The results illustrate that the superthermality index and trapping parameter play disruptive role in the formation of DLs. Likewise, the electronegativity factor plays a dominant role in the shaping of the compressive DLs. The study can be supportive to understand the behavior of nonlinear structures as observed in the nature and laboratory plasmas. (C) 2019 Elsevier B.V. All rights reserved.
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Single electron qubits are attractive for quantum information processing because they offer, for example, the possibility of extremely long coherence times. For scaling up to a large number of coupled qubits, an array of planar Pe...
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Single electron qubits are attractive for quantum information processing because they offer, for example, the possibility of extremely long coherence times. For scaling up to a large number of coupled qubits, an array of planar Penning traps is a much more promising option than the cylindrical Penning traps within which one-quantum transitions have been observed. This report summarizes optimized trap configurations, discussed at length in Goldman and Gabrielse (Phys Rev A 81:052335, 2010), which promise to make it possible to realize one-electron qubits in a scalable configuration for the first time.
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Low-field electron injection of up to 10~19 e/cm~2 across the Si-SiO_2 interface into the gate insulator of an n-channel insulated gate field effect transistor using an optically assisted hot electron injection technique was condu...
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Low-field electron injection of up to 10~19 e/cm~2 across the Si-SiO_2 interface into the gate insulator of an n-channel insulated gate field effect transistor using an optically assisted hot electron injection technique was conducted from room temperature down to 100K. It was found that the room temperature data could be modeled quite accurately by attributing all of the observed AV to generation of negatively charged defects whose generation follows a power law. At reduced temperatures, “structure” in the observed data indicated the presence of one shallow first order trap. In this case, a combination of a power law generation term and a single first order trap cross section was used, and is needed, to accurately model the data. It was also found that trap generation is enhanced significantly as the temperature is reduced. Threshold voltage shifts were shown by charge pumping measurements not to be associated with interface state generation under the low-field conditions employed. The results presented here indicate that even at very low applied oxide fields (1 MV/cm) hot electron injection not only results in the filling of existing traps, but also in the generation of new charged bulk defects whose generation rate increases as the temperature is reduced, or the injection current density is increased. These results also raise questions about some of the reports of small cross section trapping centers, ≤10~-17 cm~2, since these were boically characterized by applying a only first order trapping model to high field and/Or high current density injection data. Such aggressive injection conditions could very easily have resulted in the generation of charged bulk defects which could then be erroneously identified as one or more small cross section traps.
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This paper describes an in situ EPR study of electron trapping in a nanocrystalline rutile material. Irradiation at 4 K with broad-band UV-Vis light gives weak signals of trapped electrons. When irradiation is stopped, intense Ti~...
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This paper describes an in situ EPR study of electron trapping in a nanocrystalline rutile material. Irradiation at 4 K with broad-band UV-Vis light gives weak signals of trapped electrons. When irradiation is stopped, intense Ti~(3+) EPR signals appear, which can be removed again by resuming the irradiation. It is proposed that under irradiation there is a dynamic equilibrium established between creation of conduction band electrons, trapping of electrons, and excitation from trap sites back into the conduction band. When irradiation is stopped, conduction band electrons are trapped and remain so in the dark. Some initial results on the temperature and wavelength dependence of these processes are presented.
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A Penning trap consisting of concentric ring electrodes on a substrate and a magnetic field perpendicular to the substrate plane has been loaded with electrons. In order to demonstrate the performance of the trap we have measured ...
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A Penning trap consisting of concentric ring electrodes on a substrate and a magnetic field perpendicular to the substrate plane has been loaded with electrons. In order to demonstrate the performance of the trap we have measured the motional frequencies of the trapped electrons. Frequencies, line shape and width agree well with simulations. Miniaturization of the device is at hand which opens novel possibilities for application in quantum computing.
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A Penning trap consisting of concentric ring electrodes on a substrate and a magnetic field perpendicular to the substrate plane has been loaded with electrons. In order to demonstrate the performance of the trap we have measured ...
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A Penning trap consisting of concentric ring electrodes on a substrate and a magnetic field perpendicular to the substrate plane has been loaded with electrons. In order to demonstrate the performance of the trap we have measured the motional frequencies of the trapped electrons. Frequencies, line shape and width agree well with simulations. Miniaturization of the device is at hand which opens novel possibilities for application in quantum computing.
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A fully relativistic model of electron cyclotron current drive (ECCD) efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational ...
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A fully relativistic model of electron cyclotron current drive (ECCD) efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational approach are performed. A fully relativistic extension of the variational principle with the modified test function for the Spitzer function with momentum conservation in the electron-electron collision is described in general tokamak geometry. The model developed has generalized that of Marushchenko et al., which is extended for arbitrary temperatures and covers exactly the asymptotic for u >> 1 when Z eff >> 1, and is suited to ray-tracing and beam-tracing calculations. As a demonstration, the new model is applied in one of widely used ray-tracing codes, TORAY-GA, and yields distinct improvement on the fidelity for the calculation of ECCD in the hybrid operating scenario for the China fusion engineering test reactor.
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The process of electron trapping by a wake wave excited by a laser pulse in a plasma channel in the case where the electron bunches are injected into the vicinity of the maximum of the wakefield potential at a velocity lower than ...
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The process of electron trapping by a wake wave excited by a laser pulse in a plasma channel in the case where the electron bunches are injected into the vicinity of the maximum of the wakefield potential at a velocity lower than the wave phase velocity is considered. The mechanism for the formation of a compact electron bunch in the trapping region when only the electrons of the injected bunch that are trapped in the focusing phase mainly undergo the subsequent acceleration in the wakefield is analyzed. The influence of the spatial dimensions of the injected bunch and its energy spread on the length of the trapped electron bunch and the fraction of trapped electrons is studied analytically and numerically. For electron bunches with different ratios of their spatial dimensions to the characteristic dimensions of the wake wave, the influence of the injection energy on the parameters of the high-energy electron bunch trapped and accelerated in the wakefield is studied.
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