A method and apparatus for blasting of hard rock using a highly insensitive energetic material ignited with a moderately high energy electrical discharge causing the fracturing and break up of the hard rock is provided. The blasting apparatus (10) comprises a reusable blasting probe (14) including a high voltage electrode (44) and a ground return electrode (46) separated by an insulating tube (40). The two electrodes of the blasting probe (14) are in electrical contact with a continuous volume (70) of highly insensitive yet combustible material such as a metal powder and oxidizer mixture. The metal particles within the metal powder and oxidizer mixture form a plurality of fusible metal paths between the high voltage electrode (44) and the ground return when subjected to an electric current delivered from a large capacitor bank (16) coupled to the high voltage electrode (44). The plurality of fused metal paths act much like a fuse in that they provide a sufficiently high electrical resistance to allow coupling of the electrical energy from the capacitor bank (16) to the metal powder and oxidizer mixture causing an increased dissipation of heat which initiates an exothermic reaction of the metal powder and oxidizer mixture generating high pressure gases fracturing the surrounding rock.

Method and apparatus for blasting hard rock

Method and apparatus for plasma blasting (10) comprises a capacitor bank (28) for storing electrical charge to which is coupled an inductance (60) which delivers the electric charge as a current through a switch to an explodable conductor (16) comprising a portion of a probe (14). The explodable conductor (16) is a ribbon helically wound around a cylindrical mandril (108), the ribbon having a given length to cross section ratio of the inductance to the capacitance in order to ensure efficient dissipation of an optimal amount of the electrical energy stored in the capacitance.

Method and apparatus for plasma blasting

The method and apparatus disclosed herein relates to harnessing plasma to ignite, pressurize and distribute plasma, plasma-ignited chemical fluid and fuel throughout a propellant mass. Particularly, the present invention enables the creation of a progressive burning surface whereby the propellant reaches maximum pressure controllably and losses pressure much more slowly thus creating high piezometric efficiency. More particularly, in gun-charge-projectile systems, by using radial perforations designed to provide a balanced plasma discharge through a capillary wall and by developing forward accelerating thrust components, induced by the plasma pressure on a plasma-ignited chemical fluid and fuel mixture, the propelling charge travels down the gun tube with the projectile thus exerting substantial uniform pressure throughout the tube length and yielding a high ballistic efficiency which results in the attainment of high muzzle velocities.

Plasma actuated ignition and distribution pump

This disclosure relates to a plasma generation device particularly adapted to an electrothermal-chemical propulsion system. The device comprises a membranous conductive substance having structural compositions which enable the formation of a continuous and volumetrically distributed plasma arc. The membranous substance is versatile and operates, inter alia, as a fuse wire, plasma incubator, plasma container, plasma distributor, plasma infusion and permeation media as well as a fuel container.

Annular plasma injector

The present disclosure relates to a launch system, a launch vehicle for use with the launch system, and methods of launching a payload utilizing the launch vehicle and/or the launch system. The disclosure can provide for delivery of the payload at a terrestrial location, an Earth orbital location, or an extraorbital location. The launch vehicle can comprise a payload, a propellant tank, an electrical heater wherein propellant, such as a light gas (e.g., hydrogen) is electrically heated to significantly high temperatures, an exhaust nozzle from which the heated propellant expands to provide an exhaust velocity of, for example, 7-16 km/sec, and sliding electrical contacts in electrical connection with the electrical heater. The launch vehicle can be utilized with the launch system, which can further comprise a launch tube formed of concentric electrically conductive tubes, as well as an electrical energy source, such as a battery bank and associated inductor.

Launch vehicle and system and method for economically efficient launch thereof

A projectile is accelerated through a gun barrel in response to high pressure gas applied to the rear of the projectile in response to a high pressure plasma discharge. Plasma from the discharge flows transversely of the discharge into a chamber through multiple openings in a passage wall that confines the discharge. The high pressure, high temperature plasma flowing into the chamber causes an exothermic reaction of water and metal particles in a slurry in the chamber to produce high pressure hydrogen gas that flows longitudinally of the discharge against the rear of the projectile. To maintain the pressure of hydrogen gas acting against the projectile relatively constant as the projectile is accelerated down the barrel, electric power applied to the discharge increases substantially linearly as a function of time.

High-pressure having plasma flow transverse to plasma discharge particularly for projectile acceleration

A plasma generator (44) for an electrothermal gun cartridge has elongated metallic rod and tube members (58, 60) extending along a central axis thereof with one of the members having at least one axial gap (62) and with an elongated annular insulator located between and in engagement with both metallic members to provide support therebetween as an electrical voltage generates an electrical arc at the axial gap to provide a plasma that ignites a propellant (46). Different embodiments of the plasma generator have a plurality of the axial gaps (62) located along either the rod member (58) or the tube member (60) and are constructed for both simultaneous and sequential firing with fuses (74) controlling the timing. Helically extending member portions (78, 90) provide rotation of the electrical arc and hence the plasma generated to distribute it for ignition of the propellant (46).

Joseph R. Greig

Papers

High-pressure having plasma flow transverse to plasma discharge particularly for projectile acceleration

Plasma generator for electrothermal gun cartridge