Dimensional Envelope Research Articles

Effect of nonthermal ions on (3+1)-dimensional envelope solitary wave in magnetized PLD dusty plasma

This work investigates the envelope solitary wave (ESW) in magnetized power law distribution dusty plasma consisting of free electrons and nonthermal ions. A (3+1)-dimensional nonlinear Schr $$\ddot{o}$$ dinger equation (NLSE) through the reductive perturbation technique is derived. The nonlinear dispersion relation $$\omega =\omega (k )$$ and coefficients of NLSE are analyzed in detail by the numerical simulation method under the effect of nonthermal ions. It is indicated that the frequency increases as the number density of nonthermal ions increase. It can be seen that the frequency with higher unperturbed ion number density is larger than that with lower case. Moreover, the effects of amplitude and width on ESW are discussed with different plasma parameters. The present results can be important in understanding the characteristics of ESW for a magnetized three component plasma system.

(2+1)-dimensional dissipation nonlinear Schrödinger equation for envelope Rossby solitary waves and chirp effect**Project supported by the National Natural Science Foundation of China (Grant No. 41406018).

In the past few decades, the (1+1)-dimensional nonlinear Schrödinger (NLS) equation had been derived for envelope Rossby solitary waves in a line by employing the perturbation expansion method. But, with the development of theory, we note that the (1+1)-dimensional model cannot reflect the evolution of envelope Rossby solitary waves in a plane. In this paper, by constructing a new (2+1)-dimensional multiscale transform, we derive the (2+1)-dimensional dissipation nonlinear Schrödinger equation (DNLS) to describe envelope Rossby solitary waves under the influence of dissipation which propagate in a plane. Especially, the previous researches about envelope Rossby solitary waves were established in the zonal area and could not be applied directly to the spherical earth, while we adopt the plane polar coordinate and overcome the problem. By theoretical analyses, the conservation laws of (2+1)-dimensional envelope Rossby solitary waves as well as their variation under the influence of dissipation are studied. Finally, the one-soliton and two-soliton solutions of the (2+1)-dimensional NLS equation are obtained with the Hirota method. Based on these solutions, by virtue of the chirp concept from fiber soliton communication, the chirp effect of envelope Rossby solitary waves is discussed, and the related impact factors of the chirp effect are given.

Laser pulse propagation in inhomogeneous magnetoplasma channels and wakefield acceleration

Wakefield excitation in a preformed inhomogeneous parabolic plasma channel by an intense relativistic (≃1019 W/cm2) circularly polarized Gaussian laser pulse is investigated analytically and numerically in the presence of an external longitudinal magnetic field. A three dimensional envelope equation for the evolution of the laser pulse is derived, which includes the effect of the nonparaxial and applied external magnetic field. A relation for the channel radius with the laser spot size is derived and examines numerically to see the external magnetic field effect. It is observed that the channel radius depends on the applied external magnetic field. An analytical expression for the wakefield is derived and validated with the help of a two dimensional particle in cell (2D PIC) simulation code. It is shown that the electromagnetic nature of the wakes in an inhomogeneous plasma channel makes their excitation nonlocal, which results in change of fields with time and external magnetic field due to phase mixing ...

Universal Associative Envelopes of Nonassociative Triple Systems

We construct universal associative envelopes for the nonassociative triple systems arising from the trilinear operations of Bremner and Peresi applied to the 2-dimensional simple associative triple system. We use noncommutative Gröbner bases to determine monomial bases, structure constants, and centers of the universal envelopes. We show that the infinite dimensional envelopes are closely related to the down-up algebras of Benkart and Roby. For the finite dimensional envelopes, we determine the Wedderburn decompositions and classify the irreducible representations.

(2+1)-Dimensional Envelope Solitons in a Disk-ShapedBose-Einstein Condensate

We show that, due to the nonlinear coupling between a wavepacketsuperposed by short-wavelength collective modes and along-wavelength mean field generated by the self-interaction ofthe wavepacket, the (2+1)-dimensional envelope solitonsdecaying in all spatial directions, i.e., dromions, are possiblenonlinear excitations in a disk-shaped Bose-Einstein condensatewith a repulsive interatomic interaction.

The identification of wingless Betula fruits in Weichselian sediments in the Gross Todtshorn borehole (Lower Saxony, Germany) – the occurrence of Betula humilis Schrank.

Betula fruits lacking their wings were recovered from the Gross Todtshorn borehole, Germany, covering the late Eemian interglacial, the Early Weichselian, and the Weichselian pleniglacial. In order to identify them, a data-set of seven size and shape variables was made from modern fruits of B. pubescens, B. pendula, B. nana, and B. humilis. These measurements were summarised by principal components analysis (PCA). The 140 measured fossil fruit-bodies were positioned passively on the PCA plot and identified by comparison with the dimensional envelopes of the modern species. Tree birches (B. pendula, B. pubescens) occurred in the Eemian and Early Weichselian interstadials, but not thereafter.B. nana was widespread during the intervening stadials and the Oerel interstadial. B. humilis occurred throughout the sequence, coexisting with tree birches in the Early Weichselian and with B. nana in the stadials. It usually grew on mire surfaces, in contrast to B. nana which mainly grew on mineral substrates. However, B. nana grew on peat with B. humilis in the pleniglacial Oerel interstadial, suggesting a more continental climate with cold winters. A modern analogue could be near the Ural mountains. B. humilis is presently rare in central Europe, but during the Weichselian it was well established in northern Germany. The PCA has enabled specific determination of the wingless Betula fruits, leading to vegetational and climatic reconstructions and contributing to the previously poorly known historical biogeography of Betula humilis.

Design and issues of the ITER in-vessel components: ITER Joint Central Team and Home Teams

This paper surveys the status of the design of the in-vessel components for ITER, in particular the major components, namely the vacuum vessel, blanket and first wall, and divertor, and the interface of selected ancillary systems such as those used for RF heating and current drive, and for diagnostics. The vacuum vessel is a double-walled structure constructed from two toroidal shells joined by ribs. The space between the skins is filled with shield plates directly cooled by water. The structural material is 316 LN IG (ITER grade). Toroidal supports joining the vessel midplane ports with the TF structure limit possible differential toroidal displacements, as might occur due to seismic or vertical displacement events (VDEs). A variety of load conditions corresponding to normal and off-normal loads have been considered and in all cases peak vessel stresses are within allowables. The blanket system consists of approximately 700 modules, each weighing ∼4 t. The integrated first wall consists of a beryllium-tiled copper mat bonded to the water-cooled SS shield block. The copper mat functions as a heat sink and has imbedded in it an array of SS tubes providing water cooling. The modules are mechanically attached to a toroidal backplate. Loads due to centered disruptions are reacted via hoop stress in the backplate, whereas net vertical and horizontal loads such as those arising from VDEs are transferred through the backplate and divertor supports to the vessel. A double-wall backplate has been selected owing to structural advantages, longer coolant hold up times, and simplification of the manifold layout. Breeding blanket modules have been designed to replace the shield blanket modules within the same dimensional envelope. A solid breeder has been selected as reference breeder material. TBRs=0.8 are calculated which, together with tritium supplied from external sources, should permit a sufficient tritium supply for the EPP. The divertor design is based on a vertical target configuration. With the addition of a modest impurity fraction the divertor plasma is expected to detach from the target plates along the separatrix. The semi-detached mode of operation lowers the peak heat flux from ≥ 30 to ≤5 MW m −2. The high-heat flux (HHF) components in the divertor consist of a water-cooled copper heat sink with CFC and W tiles. A number of methods of joining CFCs, W and Be to copper are being successfully developed in the R&D program. Component testing has indicated that a heat removal of 20 MW m −2 is achievable. The divertor consists of 60 cassettes mounted on toroidal rails anchored to the bottom of the vessel. The HHF components are mounted on these cassettes and are designed to be replaceable in a hot cell. Both the blanket modules and the divertor cassettes are designed to facilitate remote replacement, with minimal turn-around time. ICRF, ECRF and NBI heating and current drive systems are under design, each at a nominal power level of 50 MW. Problems and solutions associated with RF and diagnostic interfaces are illustrated by description of the integration of ECRF, ICRF and LIDAR diagnostic systems.

Intersubband optical transitions in one dimensional quantum wire structures

One dimensional (1D) quantum wire structures are emerging as the new generation of semiconductor nanostructures offering exciting physical properties which have significant potential for novel device applications. These structures have been the subject of intensive investigation recently including extensive theoretical and experimental studies of their interband optical properties. In this work we present the results of our study of the intersubband optical transitions in 1D semiconductor quantum wires. The crescent shaped quantum wire structures used for this research were grown on non-planar GaAs substrates. The intersubband transition energy spectra, the selection rules, and the two dimensional envelope wavefunctions were theoretically investigated by using our new LENS (local envelope states) expansion. We present recent experimental results on modulation doped V-groove quantum wires, including PL, PLE, TEM, CL, and infrared polarization resolved spectroscopy. We have observed a very unusual absorption lineshape at the far-infrared wavelengths that we assigned to phonon assisted Fano resonance in a modulation doped quantum wire structure.

八分木と２段階ＦＦＴによる３次元衝突領域の高速算出

To avoid collisions of two objects such as a workpiece and a tool, computation of collision domain in which the tip of the tool cannot locate is crucial. Collision domain can well be computed by Inverted Template Method using envelope operation. In this paper, a high-speed algorithm is proposed for three dimensional envelope operation by means of convolution operation. From two input domains α and β, an envelope domain γ is quickly computed by three dimensional Fast Fourier Transform (3D-FFT). Because it needs a huge memory capacity to convolute a whole cubic space precisely at one time, octree model is adopted to represent each of whole domains α, β and γ and Double-stage FFT method is established. First, the upper parts of input octree α and β are convoluted to get the rough sketch of the envelope domain γ. Second, pairs of lower subcubes of α and β are convoluted to compute precise 3D bitmaps. Among all the pairs, only the corresponding to boundary leaf cells of the upper γ octree are extracted. Each set of bitmaps for a leaf cell is converted into a suboctree through OR operation and added under the upper tree. Comparison of computing time with a precedent algorithm shows the superiority of Double-stage FFT method.

３次元動的衝突領域の高速算出

This paper establishes a high-speed algorithm to compute three dimensional collision domain of two input domains, such as a workpiece and a tool. When the tip of the tool is located in the collision domain, the tool must collide with the workpiece. Collision domain can well be computed by Inverted Template Method using envelope operation. Studies have been made to develop algorithms for three dimensional envelope operation. In order to save on storage, oct-tree is adopted to describe three dimensional objects. An oct-tree is generated by recursive dividing of cubic cells. The top cell must involve the object to be described and the descendant cells are classified by four cell values ; outside, inside, boundary and unchecked. Among them, only boundary cells are subdivided into eight. The cell value of the output collision domain is determined by matching two cells extracted from each input domains. Matching strategy is most crucial to the speed of envelope operation. We designed three strategies ; Breadth-first, Depth-first and Weighted Depth-first-matching. Comparing the computing speeds among the three, Weighted Depth-first-matching shows the highest efficiency owing to the effect of pruning the unnecessary matching of the oct-trees.

Packing of Equal 0-Spheres

A SPHERE can be defined as the locus of a point at a constant distance from a fixed point. A sphere in n dimensions is bounded by an (n−1) dimensional envelope. This value (n−1) can be used to define the sphere; thus an 0-sphere is a sphere in one dimension, that is a pair of points on a line1.