The leading Ruelle resonances of chaotic maps

The leading Ruelle resonances of typical chaotic maps, the perturbed cat map and the standard map, are calculated by variation. It is found that, excluding the resonance associated with the invariant density, the next subleading resonances are, approximately, the roots of the equation $z^4=\gamma$, where $\gamma$ is a positive number which characterizes the amount of stochasticity of the map. The results are verified by numerical computations, and the implications to the form factor of the corresponding quantum maps are discussed.Comment: 5 pages, 4 figures included. To appear in Phys. Rev.

One-dimensional transport code for field-reversed configurations

A radial transport code for Field-Reversed Configurations (FRCs) is described. Assuming quasi-neutrality and neglecting inertia and viscous force, the evolution of particle densities, temperatures, and magnetic field through a series of equilibrium states is simulated. To solve the equations, transformations of all dependent variables and the one independent variable are carried out. The processes of interest can be decoupled into two distinctive sets of equations that describe adiabatic and nonadiabatic processes. These sets of equations are then solved by two alternating steps adiabatic and nonadiabatic