[en] An optically-isolated transmission system used in conjunction with a floating double electric probe was developed to measure directly fluctuating large amplitude electric fields and to isolate the measuring system from high common-mode voltages generated in the high-voltage straight discharge in a longitudinal magnetic field. A train of repetitive pulses of the axial electric field, frequently with the negative polarity where the electric field is directed axially from the cathode-side toward the anode-side, and with amplitude 10 kV/cm (although considerably underestimated value) was observed in close correlation with the enhanced current limitation. Moreover an intense E-field pulse, identified as a moving double layer, with amplitude typically 15 kV/cm and 30 nsec in half width was observed at the instant of abrupt current limitation. (Auth.)

[en] A model of a strong, time-independent, and relativistic double layer is studied. The model describes double layers having the electric field parallel to the current as well as a certain type of oblique double layers. From the model the ''Langmuir condition'' and the potential drop of the double layer are derived. In addition to this the distributions of the charged particles, the electric field, and the potential within the double layer are discussed. (Auth.)

[en] Experimental investigations of the evolution of oscillating double layers are presented. The oscillations are associated with the formation and destruction of a negative potential barrier on the low potential side of the double layer. (Auth.)

[en] The 'ponderomotive-force' effect causes strong repulsion of electrons from the region close to an intensely driven antenna in a space plasma. Under certain conditions, the resulting disturbed sheath around the antenna includes a region which has the essential properties of a double layer, but differs in various ways from the more usual types of double layer. (Auth.)

[en] An ion beam incident on a plane Langmuir probe gives rise to an extra knee in the electron saturation part of the current-voltage characteristic. For probe bias sufficient to reflect the beam, the beam ions contribute effectively to the charge density around the probe. A positive space charge layer is formed at the stagnation point inside the electron-rich sheath. The authors present results from an experimental and a numerical study of this double sheath formation. (Auth.)

[en] A simple method is established for the double layer (D.L.) generation in a single chamber of a double plasma (D.P.) machine at low neutral pressure and plasma density. For some experimental conditions the D.L. formation might be associated with onset of some low frequency oscillations. (Auth.)

[en] The authors present a model of double layer formation in ion acoustic turbulence excited by drifting electrons. It is found, by means of particle simulations, than when the electron drift velocity exceeds 0.6 vsub(te), a negative potential ion acoustic solitary wave first grows until its amplitude reaches to ephi approximately -Tsub(e) and subsequent reflection of electrons leads to formation of a double layer. The mechanism of the growth of the negative ion acoustic solitary wave is investigated analytically. (Auth.)

[en] A stationary, fluctuating double layer in a current-carrying magnetized plasma column is investigated by means of a retarding field electron energy analyser, Langmuir- and Faraday-cup probes and hf-probes. Most of the electrons accelerated in the double layer are, in a single transit, scattered by the hf-field produced by beam-plasma interaction. The energy spectrum is broadened and a considerable fraction of the beam electrons becomes temporarily trapped, forming an energetic, 8 eV non-isotropic population with enhanced density of low energy electrons. The trapped population, and possibly also the beam, expands across the magnetic field, also as a consequence of the hf-field, which has perpendicular components of the same magnitude as the axial. (Auth.)

[en] When the current density in the center of a neutral sheet is increased to a critical value spontaneous current disruptions are observed. The release of stored magnetic field energy results in a large inductive voltage pulse which drops off inside the plasma forming a potential double layer. Particles are energized, microinstabilities are generated, the plasma is thinned, and the current flow is redirected. These laboratory observations support qualitatively recent models of magnetic substorms and solar flares. (Auth.)

[en] Experimental observation of a potential double layer in a collisionless magnetoplasma is presented. The double layer is formed when an ion beam is injected along converging field lines produced by a permanent magnet. The height of the double layer is nearly equal to the smaller of the beam energy and the bias voltage of the magnet. The double layer is formed even when the magnet is floating, i.e., no current is drawn to the boundary. Two-dimensional potential profiles are measured. (Auth.)