where fR is the transverse part of the electron distribution function, U = U(x) is the electric potential along the x-transverse coordinate, Va is the transverse component of electron velocity, m, is the electron mass, and n,(x) is the ion density, and the latter may be considered known by using electron kinetic considerations. The solution of equations (6) and (7) is Dirac’s 3-function which is the absolute electron velocity (in both directions) in the plane of the boundary layer. These equations make it possible to determine the electron density profiles, electric field strength and electric potential in the triple D-layer. [3] The last profile has the form of a hump that thrusts ions aside in both directions and produces a high-velocity (40-60 km/s) plasma flow in one direction and a shock wave in the other. The anomalous plasma pressure may be expressed in terms of the parameters of the plasma flow: where m, is the ion mass, n is the ion (plasma) density and u is the hydrodynamic flow velocity. The lifetime of the triple D-layer is in the range of tens to hundreds of nanoseconds. Its appearance and disappearance creates broken up plasma flows. Observation of Anomalous Plasma Pressure For more than two decades it has been assumed that in impulse plasma accelerators, including those with erosion of the dielectric wall (Fig. 3a), the plasma was accelerated by Ampere forces (JxB) or by magnetic pressure difference (B2/2po). For this type of acceleration, the recoil momentum is transmitted to the current conductors via the magnetic field. The plasma-forming surface simply provides plasma material to the accelerator channel. By contrast, for the collective acceleration of ions in the triple D-layers (10'5cm), the recoil momentum from the plasma flow is transmitted to the wall by ions expelled by the positive space charge to form a shock wave in the pre-wall vapor. The role of the current conductors (including the metal rails) consists, in this case, of supplying electric power to the discharge gap.
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