23,209 research outputs found

    Spacecraft high-voltage power supply construction

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    The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing

    Planetary magnetospheres

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    A concise overview is presented of our understanding of planetary magnetospheres (and in particular, of that of the Earth), as of the end of 1981. Emphasis is placed on processes of astrophysical interest, e.g., on particle acceleration, collision-free shocks, particle motion, parallel electric fields, magnetic merging, substorms, and large scale plasma flows. The general morphology and topology of the Earth's magnetosphere are discussed, and important results are given about the magnetospheres of Jupiter, Saturn and Mercury, including those derived from the Voyager 1 and 2 missions and those related to Jupiter's satellite Io. About 160 references are cited, including many reviews from which additional details can be obtained

    Capacitance of Gated GaAs/AlGaAs Heterostructures Subject to In-plane Magnetic Fields

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    A detailed analysis of the capacitance of gated GaAs/AlGaAs heterostructures is presented. The nonlinear dependence of the capacitance on the gate voltage and in-plane magnetic field is discussed together with the capacitance quantum steps connected with a population of higher 2D gas subbands. The results of full self-consistent numerical calculations are compared to recent experimental data.Comment: 4 pages, Revtex. 4 PostScript figures in an uuencoded compressed file available upon request. Phys. Rev.B, in pres

    Anomalous Quasiparticle Symmetries and Non-Abelian Defects on Symmetrically Gapped Surfaces of Weak Topological Insulators

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    We show that boundaries of 3D weak topological insulators can become gapped by strong interactions while preserving all symmetries, leading to Abelian surface topological order. The anomalous nature of the weak topological insulators manifests itself in a non-trivial action of symmetries on the quasiparticles; most strikingly, translations change the anyon types in a manner impossible in strictly 2D systems with the same symmetry. As a further consequence, screw dislocations form non-Abelian defects that trap Z4\mathbb{Z}_4 parafermion zero modes.Comment: 6 pages, 4 figure

    Anomalous Rashba spin splitting in two-dimensional hole systems

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    It has long been assumed that the inversion asymmetry-induced Rashba spin splitting in two-dimensional (2D) systems at zero magnetic field is proportional to the electric field that characterizes the inversion asymmetry of the confining potential. Here we demonstrate, both theoretically and experimentally, that 2D heavy hole systems in accumulation layer-like single heterostructures show the opposite behavior, i.e., a decreasing, but nonzero electric field results in an increasing Rashba coefficient.Comment: 4 pages, 3 figure

    Bosonization and even Grassmann variables

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    A new approach to bosonization in relativistic field theories and many-body systems, based on the use of fermionic composites as integration variables in the Berezin integral defining the partition function of the system, is tested. The method is applied to the study of a simplified version of the BCS model.Comment: 20 pages, LaTe
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