An electron cloud due to multipacting in the positron ring of B-factories and the damping ring of the International Linear Collider (ILC) is one of the main concerns. The electron cloud in the drift region can be suppressed by a solenoid. However, the solenoid doesn’t work inside a magnet. Numerical studies show that there is strong multipacting in a dipole magnet of a B-factory positron ring. ...

To achieve fast damping, the NLC Main Damping Ring uses a wiggler with high field strength, 2.15 T, and over 45 m in length. An ideal wiggler with infinitely wide pole pieces may be treated as a linear element, and has no impact on the dynamic aperture. However, the integrated nonlinear components from a real wiggler with integrated field over 100 Tm can be significant, and the choice of method...

We present a detailed numerical study of the equilibrium and nonequilibrium dynamics of the phase transition in the finite-temperature Abelian Higgs model. Our simulations use classical equations of motion both with and without hard-thermal-loop corrections, which take into account the leading quantum effects. From the equilibrium real-time correlators, we determine the plasmon frequency, the p...

The time-optimal control of exible structures is considered. We formulate the general time-optimal control problem for single-axis exible structures, and analytical results are given for the number of control switches for the one-bending-mode case, with and without damping. When there is no damping , it is shown that the time optimal control generally has 3 switches and is an odd function of ti...

Mass-spring systems simulations rely on the numerical integration method used for solving the resulting ordinary differential equations. Implicit schemes, which solve such equations, are unconditionally stable and are thus widely used. Part of this stability is due to force filtering which is inherent to the implicit formulation and is referred to artificial damping. We extract this artificial ...

At the initial phase of the mechanical product development, it is very important to effectively obtain the modal damping ratio of the bolted joint structure for accurately predicting dynamic response. The energy dissipation has been estimated using a finite element model incorporating the effect of pretension force of the bolted joint. First, the modal damping ratios of the first four modes are...

A semiclassical method is used to study Landau damping of transverse pseudospin waves in harmonically trapped ultracold gases in the collisionless Boltzmann limit. In this approach, the time evolution of a spin is calculated numerically as it travels in a classical orbit through a spatially dependent mean field. This method reproduces the Landau damping results for spin-waves in unbounded syste...

The rate per unit volume for anomalous electroweak baryon number violation at high temperatures, in the symmetric phase, has been estimated in the literature to be O(αwT 4) based on simple scaling arguments. We argue that damping effects in the plasma suppress the rate by an extra power of αw to give O(αwT 4). We show how to understand this effect in a variety of ways ranging from an effective ...

We continue the development of the super-grid-scale model initiated in [T. Colonius, H. Ran, A super-grid-scale model for simulating compressible flow on unbounded domains, J. Comput. Phys. 182 (1) (2002) 191–212] and consider its application to linear hyperbolic systems. The super-grid-scale model consists of two parts: reduction of an unbounded to a bounded domain by a smooth coordinate trans...