für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

The modulational instability (MI) of ion-acoustic waves (IAWs) is examined theoretically in a four-component plasma system containing inertialess electrons featuring non-thermal, non-extensive distribution, iso-thermal positrons, and positively as well negatively charged inertial ions. In this connection, non-linear Schrödinger equation (NLSE), which dominates the conditions for MI associated w...

Satellite measurements show that ion beams above the auroral acceleration region are heated to hundreds of eV in a direction perpendicular to the magnetic ®eld. We show that ion acoustic waves may be responsible for much of this heating. Even in the absence of a positive slope in the velocity distribution of the beam ions, ion acoustic waves can be generated by a fan instability. We present ana...

This paper considers properties of nonlinear waves and solitons of Korteweg-de Vries equation in the presence of external perturbation. For time-periodic hamiltonian perturbation the width of the stochastic layer is calculated. The conclusions about chaotic behaviour in long-period waves and solitons are inferred. Obtained theoretical results find experimental confirmation in experiments with t...

One of the interesting observations from the FAST satellite is the detection of strong spiky waveforms in the parallel electric field in association with ion cyclotron oscillations in the perpendicular electric fields. We report here an analytical model of the coupled nonlinear ion cyclotron and ion-acoustic waves, which could explain the observations. Using the fluid equations for the plasma c...

A systematic investigation has been made of ion-acoustic solitary waves in plasma consisting of cold positively and negatively charged ions, as well as nonthermal electrons. The basic features of the solitary waves are investigated by using the reductive perturbation method, which is valid for the small but finite amplitude waves. Computational investigations have been performed to examine the ...

Surface modification of Si(100) wafers induced by argon-ion implantation (ion energy, 300keV; dose, 10" 10'' atoms/cm2) was investigated using a transient reflecting grating technique. Effects of the implantation on velocity, intensity and onset time of surface acoustic waves (SAW) were discussed accompanying the acoustic anisotropy. SAW velocity dispersion was also examined for one of the ligh...

In this paper we present the analytic solutions for two test problems involving two-fluid mixtures of dust and gas in an astrophysical context. The solutions provide a means of benchmarking numerical codes designed to simulate the non-linear dynamics of dusty gas. The first problem, DUSTYBOX, consists of two interpenetrating homogeneous fluids moving with relative velocity difference. We provid...

Multi-frequency observations of E-region coherent backscatter from decametre waves reveal that auroral echoes tend to comprise two spectral components superimposed, one at low Doppler shifts, below 250 m s−1, and the other Doppler shifted to near the ion-acoustic speed or above, up to 800 m s−1. The low Doppler shift component occurs at all look directions; Doppler shifts near the ion acoustic ...