An experiment in a linear device, the Large Plasma Device, is used to study sheaths caused by an actively powered radio frequency (rf) antenna. The rf antenna used in the experiment consists of a single current strap recessed inside a copper box enclosure without a Faraday screen. A large increase in the plasma potential was observed along magnetic field lines that connect to the antenna limite...

Abstract. This paper deals with axisymmmetry breaking instabilities in Czochralski process of crystal growth. Numerical linear stability analysis was carried out using the axisymmetric bulk flow model. Stability diagrams of critical Grashof numbers Grc and frequencies ωc dependent on aspect ratio α(=height/radius), 0.4 ≤ α ≤ 1.0 and Prandtl number Pr = 0.01 are shown. Computations were carried ...

We present time-resolved spectrophotometry of the pulsating DA white dwarf G 29-38. As in previous broad-band photometry, the light curve shows the presence of a large number of periodicities. Many of these are combination frequencies, i.e., periodicities occurring at frequencies that are sums or differences of frequencies of stronger, real modes. We identify at least six real modes, and at lea...

Measurements of frequency spectra of pressure along a wind-tunnel wall have been made by single microphones and by a longitudinal array of four flush 0.8-inch circular microphones connected with alternating and with common phase. The alternating-phase array was designed to suppress by its wavenumber filtering the background acoustic duct noise at frequencies near 3 kHz. The measured levels set ...

Fundamental barriers to advancing weather and climate diagnosis and prediction on time-scales from days to years are partly attributable to gaps in knowledge and the limited capability of contemporary operational and research numerical prediction systems to represent precipitating convection and its multiscale organization, particularly in the tropics. In this regard improvements in convective ...

Thus far, KIC 7760680 is the richest slowly pulsating B star, exhibiting 36 consecutive dipole (l = 1) gravity (g-) modes. The monotonically decreasing period spacing of the series, in addition to the local dips in the pattern, confirm that KIC 7760680 is a moderate rotator with clear mode trapping in chemically inhomogeneous layers. We employ the traditional approximation of rotation to incorp...

Some alternatives to the traditional mixing-length theory (MLT) have recently been proposed for modelling convective heat transport inside stars. The ideal formulation is one that does not involve any free parameters. However, in our present state of ignorance we still need at least one free parameter in order to build solar models with the correct radius. Having adjusted this parameter (e.g. t...

2014 We have performed experiments on the onset of turbulence in liquid 4He, as a function of the Prandtl number (0.4 Pr 0.8), for a series of cells of confined geometry with two convective rolls. For a low value of Pr the dynamic behaviour is similar to our previous studies, i.e. two frequencies followed by lock-in and subharmonic bifurcations of the lowest frequency, before the onset of turbu...

The impact of model microphysics on the relationships among hydrometeor profiles, latent heating, and derived satellite microwave brightness temperatures TB have been examined using a nonhydrostatic, adaptive-grid cloud model to simulate a mesoscale convective system over water. Two microphysical schemes (each employing three-ice bulk parameterizations) were tested for two different assumptions...