Measurement of temperature of a dusty plasma from its configuration

A new concept called “configurational temperature” is introduced in the context of dusty plasma, where the temperature of the dust particles submerged in the plasma can be measured directly from the positional information of the individual dust particles and the interaction potential between the dust grains. This method does not require the velocity information of individual particles, which is a key parameter to measure the dust temperature in the conventional method. The technique is initially tested using two-dimensional (2D) OpenMP parallel molecular dynamics and Monte Carlo simulation and then compared with the temperature evaluated from experimental data. The experiment have been carried out in the Dusty Plasma Experimental (DPEx) device, where a 2D stationary plasma crystal of melamine formaldehyde particles is formed in the cathode sheath of a DC glow discharge argon plasma. The kinetic temperature of the dust is calculated using the standard particle image velocimetry technique at different pressures. An extended simulation result for the three-dimensional case is also presented, which can be employed for the temperature measurement of a three-dimensional dust crystal in laboratory devices.     

Uniform stabilization of the damped Cauchy-Ventcel problem with variable coefficients and dynamic boundary conditions

In this paper, the uniform stabilization of the Cauchy-Ventcel problem with variable coefficients is considered, and the uniform energy decay rate for the problem is established by Riemannian geometry methods.     

Crosstalk pattern penalty reduction at 2.5 Gb/s in an SOA employing an assist light around gain transparency wavelength

We evaluate the inter-channel crosstalk in a semiconductor optical amplifier when injecting a high optical power continuous wave, as assist light, inside its active region around the gain transparency wavelength. In this work, the crosstalk of signal₁ (1535 nm) modulated at 2.5 Gb/s, has been induced by signal₂ (1560 nm) modulated at 2.5 Gb/s as well and having an optical input power of −7.5 dBm to simulate a multi-channel transmission. By measuring the bit error rate of signal₁, we show that the pattern penalty induced by the cross-gain modulation can be significantly reduced or even in certain conditions suppressed by the assist light.