The temperature profiles in wall-stabilized atmospheric-pressure arcs in pure argon and in argon–carbon dioxide mixtures have been obtained at currents of 5–40 A and for molar percentages of CO2 ranging from 0.9% to 25% using spectroscopic techniques. With the addition of CO2 to a pure-Ar arc, we show the formation of a core of higher temperatures with a larger gradient of the radial temperature distribution at the arc centre. These investigations show that the addition of even a few percent of CO2 to Ar has a marked effect both upon extinction of the arc according to current values and upon the temperature profiles. Few measurements have been done in Ar–CO2 mixtures in a wall-stabilized arc.

This paper reports the first experimental results in which the kinetic energy of cold fog, generated in a water arc plasma, exceeds the electrical energy supplied to form and maintain the arc. The cold fog explosion is produced by breaking down a small quantity of liquid water and passing a kiloampere current pulse through the plasma. The 90-year history of unusually strong water arc explosions is reviewed. Experimental observations leave little doubt that internal water energy is being liberated by the sudden electrodynamic conversion of about one-third of the water to dense fog. High-speed photography reveals that the fog expels itself from the water at supersonic velocities. The loss of intermolecular bond energy in the conversion from liquid to fog must be the source of the explosion energy.

The properties of plasma sheaths developed along plasma boundaries are investigated analytically, assuming that dielectric slabs are present between electrodes. A collisionless plasma is confined by two planar electrodes. Planar dielectric slabs with finite thickness partition the plasma into many pieces. The sheath electric field is inversely proportional to the sum of 2(1+l)+Δ/ελ, where Δ and ε are the total thickness and the relative dielectric constant respectively of the dielectric slabs, l is the number of slabs and λ is the Debye length of the high-density plasma. In this context, the plasma sheaths may easily be controlled by appropriate choices of dielectric materials and their size.

Higher-order contributions in reductive perturbation theory are studied for small- but finite-amplitude ion-acoustic solitary waves in a warm plasma with negative-ion, positron and electron constituents traversed by a warm electron beam (with different temperatures and pressures). The basic set of fluid equations are reduced to a Korteweg–de Vries (KdV) equation for the first-order perturbed potential and a linear inhomogeneous KdV-type equation for the second-order perturbed potential. At the critical negative-ion density, the coefficient of the nonlinear term in the KdV equation vanishes. A new set of stretched coordinates is then used to derive a modified KdV equation and a linear inhomogeneous modified KdV-type equation at the critical density of negative ions for the second-order perturbed potential. Stationary solutions of the coupled equations, for both cases, are obtained using a renormalization method.

Properties of global drift waves in a cylindrical weakly ionized magnetized plasma are studied analytically, and are compared with experimental observations.

Effects of dust grain charge fluctuation, obliqueness and external magnetic field on a finite-amplitude dust acoustic solitary potential in a magnetized dusty plasma, consisting of electrons, ions and charge-fluctuating dust grains, are investigated using the reductive perturbation method. It is shown that such a magnetized dusty plasma system may support a dust acoustic solitary potential on a very slow time scale involving the motion of dust grains, whose charge is self- consistently determined by local electron and ion currents. The effects of dust grain charge fluctuation, external magnetic field and obliqueness are found to modify the properties of this dust acoustic solitary potential significantly. The implications of these results for some space and astrophysical dusty plasma systems, especially planetary ring systems and cometary tails, are briefly mentioned.