On the Spatial Stabilization of the Beam-Plasma Instability

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DAAB-07-67-C-019

Dispersion Relations and Mixed Boundary Value Problems

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DAAB 07-67-C-019

Parametric Effects of Radiation on a Plasma

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DA 28 043 AMC 00073(E

Effective suppression of period-doubling in two diffusively coupled logistic maps

We consider a system of two delay diffusively coupled logistic maps. We find that for moderate values of diffusion coupling, the period-doubling sequence is effectively suppressed. Our study supports the existence of certain generic features for systems consisting of two coupled maps

Oscillations in a One-Dimensional, Inhomogenous Plasma

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryDepartment of the Army / DA-28-043-AMC-00073(E

Effect of a Boundary on the Beam Plasma Instability

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DAAB 07-67-C-019

Quenching of the Beam-Plasma Instability by Mode Mixing at a Density Discontinuity

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DAAB-07-67-C-0199 and DAAB-07-72-C-025

Heat conduction in the disordered harmonic chain revisited

A general formulation is developed to study heat conduction in disordered harmonic chains with arbitrary heat baths that satisfy the fluctuation-dissipation theorem. A simple formal expression for the heat current J is obtained, from which its asymptotic system-size (N) dependence is extracted. It is shown that the ``thermal conductivity'' depends not just on the system itself but also on the spectral properties of the fluctuation and noise used to model the heat baths. As special cases of our heat baths we recover earlier results which reported that for fixed boundaries $J \sim 1/N^{3/2}$, while for free boundaries $J \sim 1/N^{1/2}$. For other choices we find that one can get other power laws including the ``Fourier behaviour'' $J \sim 1/N$.Comment: 5 pages, 3 figures, accepted for publication in Phys. Rev. Let

Turing instability in oscillator chains with non-local coupling

We investigate analytically and numerically the conditions for the Turing instability to occur in a one-dimensional chain of nonlinear oscillators coupled non-locally in such a way that the coupling strength decreases with the spatial distance as a power-law. A range parameter makes possible to cover the two limiting cases of local (nearest-neighbor) and a global (all-to-all) couplings. We consider an example from a non-linear auto-catalytic reaction-diffusion model

Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies

We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity AGNs. We have reliably measured thetime delay between variations in the continuum and Hbeta emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R-L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hbeta time delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.Comment: 52 pages (AASTeX: 29 pages of text, 8 tables, 7 figures), accepted for publication in the Astrophysical Journa