On the conduction of a current in a plasma‐filled diode

Two issues in plasma‐filled diodes are addressed: electrostatic transient effects during the rise time of the current, and current neutralization in the bulk of the plasma. For the first issue an analytical method is used to recover some features of the diode behavior recently demonstrated in simulations [Phys. Fluids B 4, 3608 (1992)]. The potential and the electron flow are shown to be oscillatory at the initial phase of current rise, before ions start to move. The possibility of electron trapping in the potential hill is discussed. For the second issue an equilibrium is constructed that describes a plasma of dimensions larger than the electron skin depth. A beam of charged particles moves ballistically into the plasma and the plasma electrons generate a return current that neutralizes the beam current. When the plasma electrons reach the plasma boundary they bend into a skin layer and conduct the current along the plasma boundary.