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Particle dynamics and field behavior associated with a perpendicular collisionless supercritical and viscous shock are investigated by use of numerical simulation. A one-dimensional, relativistic, fully electromagnetic and nonperiodic particle simulation code (for both electrons and ions) is used where self-consistent space-charge effects and induced effects are totally included. The principal field patterns of the shock (trailing wave train, ramp, and foot region) are studied in detail and are shown to have scale lengths mainly dictated by ion dynamics; the behavior of the corresponding plasma currents associated with the different field components is also presented. Ions are shown to suffer successive ‘‘acceleration–trapping–detrapping’’ at the shock front, and locally in the trailing wave train of the downstream region through combined effects of the electrostatic and magnetic fields. While detrapped, the reflected ions describe very large Larmor orbits and cause a ring distribution; a large rapid nonstochastic ion heating results from this ion gyration. This heating (resistivity-free) is the main source of dissipation and is responsible for large field damping. Competitive effects such as particle stochasticity, particle trapping, wave damping, wave overtaking, and dispersion effects are shown to interact with each other and to affect the overall dissipation mechanism. Comparison with previous works is also discussed. Various Mach number situations are considered, leading to the definition of a transitory regime between subcritical and supercritical regimes and of a corresponding critical threshold of the electrostatic field. In contrast with the supercritical regime, the subcritical regime is characterized by a low density of trapped-reflected ions, a broad ion distribution function with a weak tail, and a weak adiabatic bulk ion heating. [ABSTRACT FROM AUTHOR]

Several experiments have evidenced oscillatory patterns of the electrostatic potential radiated by a small antenna in a hot magnetoplasma. Several previous interpretations based on analytical calculations and numerical computations are discussed; they are found not to be exhaustive or completely satisfactory. A new mechanism responsible for these structures is proposed. It consists of a filtering by the plasma of the wave vectors of the radiated waves. This mechanism is caused by the existence of a restricted range of undamped wave vectors surrounded by highly damped ones. This phenomenon, presently named ‘‘intrinsic diffraction,’’ is used to interpret both the spatial oscillations of the potential around the resonance cone when ω

Focuses on the Cerenkov emission, the interaction of an electron beam with a plasma that leads to the excitation of whistler waves. Effect of the injection of the beam at an angle with respect to the magnetic field, on whistler wave emission; Requirement for the electrostatic field to have a component perpendicular to the magnetic field during the transfer of energy.