Thermal Convection in a Central Force Field Mediated by Sound.

Convection in radial force fields is a fundamental process behind weather on Earth and the Sun, as well as magnetic dynamo action in both. Until now, benchtop experiments have been unable to study convection in radial force fields due to the inability to generate radial forces of sufficient strength. Recently, it has been appreciated that sound, when averaged over many cycles, exerts a force on density gradients in the gas it travels through.

Imaging suprathermal x-rays from a laboratory plasma jet using PIN-diode-based and scintillator-based 1D pinhole/coded aperture cameras.

A PIN-diode-based 1D x-ray camera and a scintillator-based 1D x-ray camera, both with a microsecond to submicrosecond time resolution, have been developed to perform time-resolved imaging of transient, low-intensity, suprathermal x-rays associated with magnetohydrodynamic instabilities disrupting a plasma jet. These cameras have a high detection efficiency over a broad x-ray band, a wide field of view, and the capability to produce >50 time-resolved frames with a ≤1 μs time resolution. The x-ray images are formed by a pinhole or by a coded aperture placed outside a vacuum chamber in which the plasma jet is launched.

First Nationwide Monitoring Program for the Detection of Potentially Invasive Mosquito Species in Austria.

In Austria, only fragmented information on the occurrence of alien and potentially invasive mosquito species exists. The aim of this study is a nationwide overview on the situation of those mosquitoes in Austria. Using a nationwide uniform protocol for the first time, mosquito eggs were sampled with ovitraps at 45 locations in Austria at weekly intervals from May to October 2020.

Acoustic self-oscillation in a spherical microwave plasma.

We present a method of sound amplification and self-oscillation in high pressure partially ionized gas. Continuous microwaves incident on partially ionized gas may sustain and amplify an acoustic field if increased ionization during the sound field's adiabatic compression enhances rf power absorption. Amplifying sound in this way enables the generation of high amplitude sound in a cavity containing partially ionized gas without mechanical driving or precise knowledge of its resonance frequency.

Acoustic resonances in gas-filled spherical bulb with parabolic temperature profile.

Acoustics is used to probe the temperature profile within a sulfur plasma lamp. A spherically symmetric temperature profile is assumed that drops with the square of the radius, consistent with a constant volumetric heating model. Acoustic resonance frequencies are calculated exactly in the case of an ideal gas.