The present study aimed to identify threshold shear stresses to cause benthic invertebrates to drift in boundary shear layers. Laboratory experiments were carried out in a small tilting flume, 10 cm wide and 3 m long with a closed recirculation system and a fixed sand bottom of uniform grain size. Benthic invertebrates from different orders (Achaeta, Gastropoda, Crustacea, Ephemeroptera, Odonat...

Abstract The calculation of fusion reactivity involves a complex six-dimensional integral that takes into account the cross section and velocity distributions two reactants. However, more simplified one-dimensional form can be useful in certain cases, such as for studying yield or diagnosing ion energy spectra. This simpler has been derived few special combination Maxwellian distributions, beam...

– We demonstrate via several examples that a uniform drift velocity gives rise to anomalous aging, characterized by a specific form for the two-time correlation functions, in a variety of statistical-mechanical systems far from equilibrium. Our first example concerns the oscillatory phase observed recently in a model of competitive learning. Further examples, where the proposed theory is exact,...

Previous research which analyses the dynamics of a “subsonic”, constantψ, magnetic island propagating through a two-fluid, drift-MHD (magnetohydrodynanical) plasma in slab geometry is extended to cover “supersonic” islands. In the subsonic limit, the phase-velocity of an isolated island is simply the (perpendicular) viscosity weighted mean of the unperturbed ion and electron fluid velocities. H...

We simulate short positive and negative streamers in air at standard temperature and pressure. They evolve in homogeneous electric fields or emerge from needle electrodes with voltages of 10 to 20 kV. The streamer velocity at given streamer length depends only weakly on the initial ionization seed, except in the case of negative streamers in homogeneous fields. We characterize the streamers by ...

The CUTLASS Finland radar, which comprises an integral part of the SuperDARN system of HF coherent radars, provides near continuous observations of high-latitude plasma irregularities within a ®eld-ofview which extends over some four million square kilometres. Within the Finland radar ®eld-of-view lie both the EISCAT mainland and EISCAT Svalbard incoherent scatter radar facilities. Since the CU...

The Monte Carlo method was shown to be a very powerful technique in solving the Boltzmann equation by particle simulation. Its simple concept, straightforward algorithm, and its adaptability to include new features (such as, gravity, electric field, geomagnetic field, and different collision models) make it useful tool in space plasma physics, and a powerful test of results obtained with other ...