Description:
Invention Summary
Typically, laboratory plasma discharges are either of the DC or AC type used in numerous fields such as sputtering, plasma etching, plasma assisted material device technology, etc. Such discharges occur at pressures well below the 1 Torr (133.33 Pa) pressure. Further, plasma discharges occurs in high voltage hold-off gas switches, plasma arc welding, lightening, etc. at atmospheric and higher pressures. At pressures above 1 Torr and less than atmospheric pressures, the plasma discharge tends to violently transform to a plasma arc. Like the principle of the lightening rod, field enhancements occur at edges and sharp points thereby resulting in environment breakdown and electrical discharging. Under pulsed conditions in a parallel plate discharge, there appears to be unique parameter space in pressure and voltage where the glow discharge (not arc) pinches and forms a suitable discharge away from field enhancement regions. Further, the discharge can be externally controlled and tuned. A competition between Paschen effects and collision probabilities leads to a parameter space in which the plams density can be varied with minimal arcing effect way from the edge of the parallel plate electrodes. Operating on the right hand side of Paschen curve assuming that the distance of separation between the plates is fixed, as the pressure increases the breakdown voltage increases. Increasing the breakdown voltage stores more charge on the parallel plate electrodes thereby increasing the electric field between the plates needed to accelerate the charge. In particular, the discharge is composed of at least three flavors of charge: positive heavy background ions, light background electrons, and fast beam electrons. If the energetic beam-electrons have accelerated to high enough kinetic energies prior to entering the glow discharge region, the probability that a collision will occur decreases with increases in beam energy. Consequently, the fast electrons do not significantly lose their initial kinetic energy. Assuming that they are moving in one rectilinear direction as dictated by the presence of the cathode and anode dark spaces supporting the majority of the potential difference between the plates, in simplest terms, the background electrons experience the Coulomb fields of the fast electron beam and repel perpendicular to the beam out of the region occupied by the fast electrons. This repulsion effect continues until a quasi-neutrality among the three charge species result and a minimum electrical space charge energy is achieved. The self magnetic forces of the fast electrons then dominates causing the fast electron beam to pinch which leads to a new concentration state where the net charge is not zero. Electric space charge effects ensue and the process continues until an ultimate equilibrium state arises. Here we have purposely omitted the thermal effects to simply pose the basic physics of this discharge process. This process is electron beam energy and charge/neutral density sensitive. At lower beam energies, the pinch degrades and the plasma discharge eventually covers the entire electrode surface. |This process is a pulsed process needed to intermittently maintain the large electric fields that are constantly being shorted to lower values when the glows discharge event results. Having control over the glow plasma discharge pinch, one can control the pinch density, pinch diameter, and pinch intensity. The degree of electromagnetic wave reflection, scattering, and absorption is determined by the plasma density. Lower frequency waves tend to be reflected, scattered, or absorbed more than high frequency waves from a plasma.
Market Opportunity
As a result, plasmas at high enough density may be used to disrupt a high power EMP or high power CW wave to prevent electronic attack. Here electronic attack extends to electronic equipment on the battle field, satellites orbiting in space responsible for our nation's and world's cyber infrastructure, and electronic equipment in industry susceptible to high electromagnetic field environment. In each of the cases, the plasma discharge would be set up to be auto triggered by the attacking stimulus electromagnetic field.
Features & Benefits
Because a plasma wire configuration may be attained and the plasma in its own right has a noisy signature, it is possible to purposely embed communication signals in the wire's noise environment used as a form of camouflage. It may be possible to increase the longevity of high voltage gas switches if the discharge may be engineered as a glow discharge as compared to an arc (or explosive arc) discharge as far as electricity conducted through the wire. The trigger could be electrical or electromagnetic (e.g., laser beam, etc.). Since one has the ability to control the plasma density, it is anticipated that the invention may be used as an all inclusive microwave switch and/or filter or beam splitter to external waves and as a controlled plasma density source for interactions with solid state materials (e.g. controlled "massaging" of diamond materials to relieve stress, etc.).
Intellectual Property
Issued US Patent No.: US 10,135,236 B2