US Government As Represented by the Secretary of the Army

Raymond W Conrad

Thomas G Roberts

Thomas E Honeycutt

William F Otto

Aryeh Kidron

A superconducting, superdirective antenna array wherein a superconductive terial is employed for the elements of the array which are arranged in a uniform half-wave dipole has low ohmic resistance and a very high radiation efficiency. The superdirective antenna array which is a linear array has element spacing less than .lambda.o/2 where .lambda.o is the center frequency of the dipoles. The material of the array elements has a very high critical current (i.e., and a critical magnetic field), a requirement for maximum efficiency. The superconducting, superdirective antenna array is housed in a vacuum insulated container and is provided outlet connecting to means for obtaining and sustaining a vacuum as required for element material of fabrication. The material of fabrication for the antenna array elements is selected from a type II superconductor material selected from the group consisting of iridiumm, lead, mercury, tantalum, vanadium, a composite of niobium-tin-bronze, and alloys of the same. The antenna array element material of fabrication, as fabrication techniques become available, can be a superconductive material selected from the ceramic oxides composition group consisting of La.sub.2-x Ba.sub.x CuO.sub.x and YBa.sub.2 Cu.sub.3 O.sub.x wherein x is an integer and wherein the transition temperature ranges from about 30.degree. K. to about 93.degree. K., and the thallium-calcium-barium-copper oxide family of compounds with a transition temperature as high as 125.degree. K. A dielectric window is employed for directing radiation of a very high directivity from the superconducting, superdirective antenna array.

Superconducting, superdirective antenna array

An aircraft collision warning system in which a low power pulsed laser sym projects narrow bandwidth radiation into 4.pi. steradians around an aircraft and a matched, narrow bandwidth receiver system, with a 4.pi. steradian field-of-view which detects such radiation emitted from another aircraft within range of the receiver and activates appropriate warning.

Aircraft collision warning system

A polydisperse aggregate of very small solid particles that form voids therebetween with a lasing dye solution in said voids to form a laser host medium is disclosed.

Laser medium for dye lasers

A system for measuring the density of certain ions or neutrals within a plasma without probe intervention. When cylindrical symmetry is present, the system also provides measurement of spatial distribution of excited ionic states within the plasma. The system allows spatial distribution of contaminant ions in magnetic confinement thermonuclear fusion devices to be monitored. These functions are accomplished by directing two laser beams through a region containing a plasma. The laser means are at respective wavelengths chosen to be in and closely adjacent to a spectral region near the electronic transition frequency of the ionic species of interest in the plasma. The intensities of the two wavelengths are then measured and compared to obtain the desired data and characterization.

Apparatus for plasma diagnostics

The meter consists of wire resistors arranged so as to sample the energy in a laser beam at different locations in the beam. Each resistor is part of a bridge which includes three other resistors, a power source, a detector (volt meter) and a display unit which may be a recorder. One of the three additional resistors may be an additional set of wires which are made nearly identical to the set being used to sense the laser beam's position or to determine its intensity distribution. When the wire resistors are exposed to the laser beam the wires are heated, their resistance changes, and the various bridges become unbalanced. The magnitude of the voltage produced in each bridge is proportional to the energy in the laser pulse at the location of each wire.

Precision laser beam positioner and spatially resolved laser beam

A laser spot tracker having a wider field-of-view by the use of a phase draction plate to cause the focusing of a square array of spots upon a focal plane having a plurality of detectors thereon. Using the detectors to find the spot of the greatest intensity so as to cause the tracker to point towards the target of interest.

Wide field-of-view laser spot tracker

A device for the passive location of irradiance display of high power infed beams at remote locations utilizing the combination of reflecting material with high thermal conductivity and an absorbing refractory material with high emissivity in the visible portion of the electromagnetic spectrum.

High power laser irradiance display material

An irradiance analysis system which includes an array of square rods that are joined together and have a flat entrance end and a polished flat exit end through which visible light is transmitted to a Fresnel lens and focused to a particular area where the image focused is photographed so that when the various frames are developed they can be analyzed in a conventional film densitometer to yield quantative data on the temporal variation of laser beam irradiance distributions.

Irradiance analyzer for high power lasers

Plasma generation occurs when radiation from a high power, infrared laser is directed to a sufficiently short focal point to produce the irradiance required for producing a plasma or laser-supported combustion wave, with the assistance of external plasma initiation apparatus such as an electrode discharge. The laser beam is directed through a cylindrical or conical chamber to the electrode discharge means. The chamber allows a controlled flow of gas to be introduced into the chamber, flowing in the direction of the laser beam to exhaust at the end of the chamber. A plasma is ignited, using the plasma initiation device and is prevented from propagating up the laser beam by the opposing flow of gas. The position of the plasma along the laser beam axis and the plasma temperature are controlled by the velocity of the gas flow. As the gas velocity is increased, the plasma is forced to retreat into higher intensity regions of the converging laser beam, where it absorbs more energy from the beam thereby reaching higher temperatures.

Laser plasmatron

Disclosed is a method and device for the fixation of atmospheric nitrogen ilizing the very high temperature and rapid quenching rates of plasmas produced by the focused beam of a repetitively-pulsed, high energy laser. The irradiance at the focal point of a mirror employed in the nitrogen fixation reaction chamber exceeds that required for plasma production in clear air, namely: 10.sup.9 watts/cm.sup.2 at 10.6 micrometers; consequently, a plasma is produced every time the laser pulses. The laser pulse length being short causes rapid quenching of the plasma thereby preventing decomposition of the nitric oxide formed from a mixture of nitrogen and oxygen introduced at an elevated pressure through an inlet to the nitrogen fixation reaction chamber. The reaction gas mixture containing the nitric oxide is extracted from the reaction chamber through an outlet means. The nitric oxide is subsequently removed by scrubbing with water, or by other extraction techniques well established in the art.

Nitrogen fixation with a high energy laser

A method and apparatus for initiating a stable plasma and maintaining the asma stationary. A high power, continuous wave laser is used to initiate and maintain the plasma, while a magnetic trap confines the plasma.

Growing community of inventors

Russellville, AL, United States of America

Raymond W Conrad