DOUBLE LAYERS in Plasma Physics
anode – a positive terminal
cathode – a negative terminal or electrode
electrode – a conductor by which electricity enters or leaves an object substance, or region
Vast amounts of energy are required by the technologies being used to manipulate the planet’s climate systems, the jet stream, etc. Plasma physics is the base of all these technologies, fusion Tokamak, HAARP, the rf/microwave transmitters, electronic warfare and more. In the textbook “Physics of the Plasma Universe” Anthony L. Peratt explains ‘Double Layers’:
The double layer consists of two thin and close regions of opposite charge excess, which give rise to a potential drop, and therefore an electric field, across the layers. The ions and electrons inside the double layer are accelerated in opposite direction along the magnetic field by the electric field. The ions accelerate towards the cathode (a negative terminal conducting electricity) while the electrons accelerate towards the anode (a positive terminal conducting electricity).
Double layers carry electric currents. If an electrical discharge is produced between an anode and a cathode, a ‘sheath’ forms and serves to accelerate electrons that carry a current through the plasma. This ‘sheath’ is made of up a ‘virtual cathode’ and a ‘virtual anode’, thus the lateral limitation of the plasma is produced by double layers.
Birkeland currents (charged particles follow magnetic lines of force and produce field-aligned currents) flowing between the ionosphere and magnetosphere may produce a series of double layers as the currents flow through regions with different densities.
Double layers may form to ‘cellularize’ the plasma into more or less homogenous regions. Double layers are also formed when the current through a plasma is increased by increasing the applied voltage; the plasma then divides itself into two analogous the a biological cell.
Concomitant with double layers are noise (rapid variations within a broad spectral band) and rapid fluctuations. The noise in effect ‘scatters’ the electrons and this can greatly exceed the scattering due to collisions between electrons.
Since double layers form in electric currents, the double layer itself can be considered an element within the complete electrical circuit. Every circuit contains intrinsically explosive inductive energy which is mainly used for accelerating charged particles, localized heating and radiation.
Plasma Physics and Radiation Technology
In this cluster two main lines of research are being pursued. The first line encompasses the study of excitation, transport, kinetics and non-equilibrium phenomena associated with the plasma state and the plasma-surface interface. These are important in plasma processing and in the generation of light by plasmas. The processing involves deposition and etching of new materials (solar cells), as well as cleaning of waste fluids and gases.
Light generation by plasma sources is being studied over the range from infrared to extreme ultraviolet.
The second line of research addresses a range of plasma phenomena in the physics of ultra-high-brightness electron beams. Here one is dealing with plasmas in extreme conditions – high density, high power density, short lived, fully ionized – which form an essential ingredient in the search for acceleration and light generation in compact structures. The long-term goal is the development of a compact accelerator for driving various schemes to generate extreme ultraviolet radiation, ultimately including a free-electron laser.