排序方式: 共有44条查询结果,搜索用时 15 毫秒
1.
Gekelman W. Maggs J.E. Pfister H. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1992,20(6):614-621
A series of experiments on the dynamic interaction of two current channels has been performed in the large plasma device, a laboratory device at UCLA. The two current channels are formed by coating the cathode source nonuniformly and then biasing it with respect to an anode 10 m away. The experiment consists of two phases, one in which a net current is drawn through the plasma, and one in which the net current is zero. The current channels twist about each other, merge, and evolve toward a force-free state when a net current is drawn through the plasma. When the net current is zero the interaction between the channels is greatly reduced. The dynamics of the system are dominated by electron pressure and associated electrostatic fields. However, as the currents twist, a small amount of magnetic helicity is generated. The helicity and its temporal rate of change are computed and found to compare within experimental uncertainty to the predicted rate 相似文献
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We introduce a Monte Carlo algorithm for the simulation of charged particles moving in the continuum. Electrostatic interactions are not instantaneous as in conventional approaches, but are mediated by a constrained, diffusing electric field on an interpolating lattice. We discuss the theoretical justifications of the algorithm and show that it efficiently equilibrates model electrolytes and polar fluids. In order to reduce lattice artifacts that arise from the interpolation of charges to the grid we implement a local, dynamic subtraction algorithm. This dynamic scheme is completely general and can also be used with other Coulomb codes, such as multigrid based methods. 相似文献
4.
Gekelman W. Maggs J. Bamber J. Vincena S. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(1):20-21
In a laboratory experiment, whistler waves are launched toward a field-aligned density gradient. Characteristic scale length and frequency ratios were carefully scaled to reproduce situations found in the auroral ionosphere. The experiment clearly shows the direct conversion of whistler waves to largely electrostatic lower hybrid waves 相似文献
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R. J. Maggs 《Chromatographia》1968,1(1-2):53-56
Résumé Le détecteur décrit dans ce mémoire apporte une contribution aux progrès de la chromatographie en phase liquide. Avec un appareil de ce genre on peut étudier les paramètres des colonnes afin de pouvoir juger de leurs performances. L'existence de deux méthodes de détection élargit le champ d'application du détecteur à fil mobile. Le modèle à Argon [21] sera finalement te plus sensible de ces détecteurs à cause de sa plus grande efficacité d'ionisation alors que le modèle D.I.F. [22] a l'avantage d'une plus haute température de fonctionnement permettant de réduire le risque de condensation du soluté (ou de ses produits de pyrolyse) pendant l'expérience. 相似文献
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We study thermal Casimir and quantum nonretarded Lifshitz interactions between dielectrics in general geometries. We map the calculation of the classical partition function onto a determinant, which we discretize and evaluate with the help of Cholesky factorization. The quantum partition function is treated by path integral quantization of a set of interacting dipoles and reduces to a product of determinants. We compare the approximations of pairwise additivity and proximity force with our numerical methods. We propose a "factorization approximation" that gives rather good numerical results in the geometries that we study. 相似文献
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O (c+d) steps using constant-size queues, where c is the congestion of the paths in the network, and d is the length of the longest path. The proof, however, used the Lovász Local Lemma and was not constructive. In this paper,
we show how to find such a schedule in time, with probability , for any positive constant β, where is the sum of the lengths of the paths taken by the packets in the network, and m is the number of edges used by some packet in the network. We also show how to parallelize the algorithm so that it runs
in NC. The method that we use to construct the schedules is based on the algorithmic form of the Lovász Local Lemma discovered
by Beck.
Received: July 8, 1996 相似文献
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Maggs AC 《Physical review letters》2006,97(19):197802
We introduce a multiscale Monte Carlo algorithm to simulate dense simple fluids. The probability of an update follows a power law distribution in its length scale. The collective motion of clusters of particles requires generalization of the Metropolis update rule to impose detailed balance. We apply the method to the simulation of a Lennard-Jones fluid and show improvements in efficiency over conventional Monte Carlo and molecular dynamics simulations, eliminating hydrodynamic slowing down. 相似文献
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We consider a problem in dynamically constrained Monte Carlo dynamics and show that this leads to the generation of long ranged
effective interactions. This allows us to construct a local algorithm for the simulation of charged systems without ever having
to evaluate pair potentials or solve the Poisson equation. We discuss a simple implementation of a charged lattice gas as
well as more elaborate off-lattice versions of the algorithm. There are analogies between our formulation of electrostatics
and the bosonic Hubbard model in the phase approximation. Cluster methods developed for this model further improve the efficiency
of the electrostatics algorithm. 相似文献
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O'Neill PM Bishop LP Searle NL Maggs JL Storr RC Ward SA Park BK Mabbs F 《The Journal of organic chemistry》2000,65(5):1578-1582