A virtual cathode
is produced in this device by a nonthermal electron plasma confined in a modified-geometry Penning trap.
The key technologies which may be applied to electromagnetic munitions design in the near term are explosively pumped flux compression generators (FCGs) and high-power microwave (HPM) devices, the most important of which is the virtual cathode oscillator, or vircator.
High-Power Microwave Devices - the Virtual Cathode Oscillator
The electrons which have passed the anode form a bubble of space charge, termed a virtual cathode, behind the anode.
This volume of cells, known as the virtual cathode for that shock, initiates electric stimulation of the rest of the heart.
Using the bidomain model and fluorescent dye methods, the Vanderbilt team predicted that there would be an excessively positive, or hyperpolarized, area on either side of the virtual cathode. This area, which they call the virtual anode, resists electric stimulation and fails to propagate the impulse.
Knisely says that understanding the virtual cathode and anode may allow researchers to find better ways to lengthen that refractory period.
Such oscillations in linear relativistic electron beams may be caused either by the formation of virtual cathodes
(when an injected beam current exceeds the limiting current defined by space-charge effects) or by low-potential electrodes reflecting streaming particles.