The transverse dynamics of space-charge dominated beams are investigated both analytically and computationally, in order to understand the mechanisms for emittance oscillations and growth due to nonlinear space-charge fields. This work explores the role of space-charge dominated equilibrium and its relationship to phase space wave breaking, which is responsible for the irreversible emittance gr...

We study the totally asymmetric simple exclusion process (TASEP) on complex networks, as a paradigmatic model for transport subject to excluded volume interactions. Building on TASEP phenomenology on a single segment and borrowing ideas from random networks we investigate the effect of connectivity on transport. In particular, we argue that the presence of disorder in the topology of vertices c...

Mathematical models of transport of radioactive contaminants in flowing groundwater involve large systems of coupled advection dominated transport equations. High-resolution explicit finite volume methods, if applied to advective part of model and combined with appropriate numerical methods for diffusion-dispersionreaction part, can offer precise and monotone numerical solutions, but they requi...

In this paper, we present special discretization and solution techniques for the numerical simulation of the Lattice Boltzmann equation (LBE). In [11] the concept of the generalized mean intensity had been proposed for radiative transfer equations which we adapt here to the LBE, treating it as an analogous (semi-discretized) integro-differential equation with constant characteristics. Thus, we ...

In this paper, we apply special techniques from Numerics for PDE’s to the Lattice Boltzmann equation. In [5] the concept of the generalized mean intensity has been proposed for radiative transfer equations. Here, we adapt this concept to the LBE, treating it as an analogous integro differential equation with constant characteristics. Thus, we combine an efficient finite differencelike discretiz...

We report theoretical and experimental evidence for transverse modulational instability of two counterpropagating beams in a photorefractive medium with no external feedback. A frequency detuning is applied to one of the beams in order to drive the system to instability. We perform a linear-stability analysis that allows for detuning of the counterpropagating pump beams in addition to an additi...

Controlled tile drainage (CTD) can reduce pollutant loading. The Annualized Agricultural Nonpoint Source model (AnnAGNPS version 5.2) was used to examine changes in growing season discharge, sediment, nitrogen, and phosphorus loads due to CTD for a ∼3900-km agriculturally dominated river basin in Ontario, Canada. Two tile drain depth scenarios were examined in detail to mimic tile drainage cont...

Topological superconductivity is an exotic state of matter that supports Majorana zero-modes, which have been predicted to occur in the surface states of three-dimensional systems, in the edge states of two-dimensional systems, and in one-dimensional wires. Localized Majorana zero-modes obey non-Abelian exchange statistics, making them interesting building blocks for topological quantum computi...

The principles underlying a proposed class of black hole accretion models are examined. The flows are generally referred to as “convection-dominated,” and are characterized by inward transport of angular momentum by thermal convection and outward viscous transport, vanishing mass accretion, and vanishing local energy dissipation. In this paper we examine the viability of these ideas by explicit...