Hamiltonian approach to slip-stacking dynamics

Hamiltonian dynamics has been applied to study the slip-stacking dynamics. The canonical-perturbation method is employed to obtain the second-harmonic correction term in the slip-stacking Hamiltonian. The Hamiltonian approach provides a clear optimal method for choosing the slip-stacking parameter and improving stacking efficiency. The dynamics are applied specifically to the Fermilab Booster-Recycler complex. The dynamics can also be applied to other accelerator complexes.Comment: 10 p

Public wrongs and the criminal law

This paper is about how best to understand the notion of ‘public wrongs’ in the longstanding idea that crimes are public wrongs. By contrasting criminal law with the civil laws of torts and contracts, it argues that ‘public wrongs’ should not be understood merely as wrongs that properly concern the public, but more specifically as those which the state, as the public, ought to punish. It then briefly considers the implications that this has on criminalization.AHRC (AH/H015655/1

Control of space stations

A study is made to develop controllers for the NASA-JSC Triangular Space Station and evaluate their performances to make recommendations for structural design and/or control alternatives. The control system design assumes the rigid body of the Space Station and developes the lumped parameter control system by using the Inverse Optimal Control Theory. In order to evaluate the performance of the control system, a Parameter Estimation algorithm is being developed which will be used in modeling an equivalent but simpler Space Station model. Finally, a scaled version of the Space Station is being built for the purpose of physical experiments to evaluate the control system performance

Antipersistant Effects in the Dynamics of a Competing Population

We consider a population of agents competing for finite resources using strategies based on two channels of signals. The model is applicable to financial markets, ecosystems and computer networks. We find that the dynamics of the system is determined by the correlation between the two channels. In particular, occasional mismatches of the signals induce a series of transitions among numerous attractors. Surprisingly, in contrast to the effects of noises on dynamical systems normally resulting in a large number of attractors, the number of attractors due to the mismatched signals remains finite. Both simulations and analyses show that this can be explained by the antipersistent nature of the dynamics. Antipersistence refers to the response of the system to a given signal being opposite to that of the signal's previous occurrence, and is a consequence of the competition of the agents to make minority decisions. Thus, it is essential for stabilizing the dynamical systems.Comment: 4 pages, 6 figure

Every Good Virtue You Ever Wanted in a Q-switched Solid-state Laser and More: Monolithic, Diode-pumped, Self-q-switched, Highly Reproducible, Diffraction-limited Nd:yag Laser

The applications of Q-switched lasers are well known, for example, laser radar, laser remote sensing, satellite orbit determination, Moon orbit and 'moon quake' determination, satellite laser communication, and many nonlinear optics applications. Most of the applications require additional properties of the Q-switched lasers, such as single-axial and/or single-transverse mode, high repetition rate, stable pulse shape and pulse width, or ultra compact and rugged oscillators. Furthermore, space based and airborne lasers for lidar and laser communication applications require efficient, compact, lightweight, long-lived, and stable-pulsed laser sources. Diode-pumped solid-state lasers (DPSSL) have recently shown the potential for satisfying all of these requirements. We will report on the operating characteristics of a diode-pumped, monolithic, self-Q-switched Cr,Nd:YAG laser where the chromium ions act as a saturable absorber for the laser emission at 1064 nm. The pulse duration is 3.5 ns and the output is highly polarized with an extinction ratio of 700:1. It is further shown that the output is single-longitudinal-mode with transform-limited spectral line width without pulse-to-pulse mode competition. Consequently, the pulse-to-pulse intensity fluctuation is less than the instrument resolution of 0.25 percent. This self-stabilization mechanism is because the lasing mode bleaches the distributed absorber and establishes a gain-loss grating similar to that used in the distributed feedback semiconductor lasers. A repetition rate above 5 KHz has also been demonstrated. For higher power, this laser can be used for injection seeding an amplifier (or amplifier chain) or injection locking of a power oscillator pumped by diode lasers. We will discuss some research directions on the master oscillator for higher output energy per pulse as well as how to scale the output power of the diode-pumped amplifier(s) to multi-kilowatt average power