Fast quasiadiabatic dynamics

Quasiadiabatic description of nonlinear particle dynamics in typical magnetotail configurations

In the present paper we discuss the motion of charged particles in three different regions of the Earth magnetotail: in the region with magnetic field reversal and in the vicinities of neutral line of Xand O-types. The presence of small parameters (ratio of characteristic length scales in and perpendicular to the equatorial plane and the smallness of the electric field) allows us to introduce a...

Quasiadiabatic modes from viscous inhomogeneities

The viscous inhomogeneities of a relativistic plasma determine a further class of entropic modes whose amplitude must be sufficiently small since curvature perturbations are observed to be predominantly adiabatic and Gaussian over large scales. When the viscous coefficients only depend on the energy density of the fluid the corresponding curvature fluctuations are shown to be almost adiabatic. ...

Quasiadiabatic switching for metal-island quantum-dot cellular automata

Recent experiments have demonstrated a working cell suitable for implementing the quantum-dot cellular automata ~QCA! paradigm. These experiments have been performed using metal-island clusters. The most promising approach to QCA operation involves quasiadiabatically switching the cells. This has been analyzed extensively in gated semiconductor cells. Here we present a metal-island cell structu...

Slow-fast Dynamics in Wonderland

A fast multipole method for stellar dynamics

The approximate computation of all gravitational forces between N interacting particles via the fast multipole method (FMM) can be made as accurate as direct summation, but requires less thanO (N) operations. FMM groups particles into spatially bounded cells and uses cell-cell interactions to approximate the force at any position within the sink cell by a Taylor expansion obtained from the mult...