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Finite amplitude ion-cyclotron and ion-acoustic waves and solitons propagating obliquely in a magnetized warm-ion plasma are considered using exact ion dynamics and quasi-neutrality. The effect of finite ion temperature is to decrease the amplitude of the soliton and increase its width. The behaviour of the amplitudes of ion-cyclotron and ion-acoustic waves is studied as a function of EO, where EO is

Acute (4 day) and short-term (7 day) toxicity studies (at 1/5th and 1/10th of LC(50)) of textile dye wastewaters and their selected ingredients (azo dye methyl red and heavy metals Cd, Cu, Ni and Zn) were made on a freshwater fish Gambusia affinis under laboratory conditions. LC(50) value was found to be the lowest in four cases, and the EC(50) value for reduction in erythrocyte counts in the remaining four tests. Thus, the reduction in erythrocyte counts to the 50% level was similar in sensitivity to fish mortality. The short-term toxicity studies revealed significant disorders in erythrocyte morphology (poikilocytosis) and its counts to be the better indices for toxicity monitoring in the absence of fish mortality.

A theoretical analysis of acoustic-like modes in a plasma consisting of two kinds of ions with different temperatures has been performed using fluid equations. The electrons are assumed to form a dynamic neutralizing background, and their perturbation has been neglected – which is permissible for k2λ2De ≫ 1. The analysis shows that an acoustic-like mode appears to propagate as a normal mode when the hotter ion concentration is very large compared with that of the colder ions.

The stability of oblique modulation of ion-acoustic waves in a collisionless plasma consisting of two cold-ion species with different masses, concentrations, and charge states, and hot isothermal electrons is studied. Using the Krylov–Bogoliubov–Mitropolosky (KBM) perturbation technique, a nonlinear Schrödinger equation governing the slow modulation of the wave amplitude, is derived for the system. It is found that the presence of second-ion species significantly changes the instability domain in the k-φ plane. The effect of charge state, concentration, and mass of second-ion species on the modulational instability is discussed in detail. The predictions of the theory are found to be in good agreement with the experimental observations.

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Propagation of an ion-acoustic soliton in an ion-beam plasma system is studied using the renormalization procedure of Kodama and Taniuti in the reductive perturbation method and an alternative method. Expressions for the first- and second-order potentials are derived. The effects of beam velocity and beam density on the amplitude and the width of the solitons, for different ion-mass ratios, are considered. It is found that (i) the amplitude decreases with the increase of beam density, and (ii) there is a critical beam velocity, below which a stationary soliton cannot exist in an ion-beam plasma system.