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A highly efficient TM010 resonant cavity operating at 2.45 GHz has been shown to produce an external surface wave plasma propagating in the TM01 mode at atmospheric pressure. The evanescent radial electric field of this surface wave plasma has been used as a detector for gas chromatography. The detector is based on monitoring the electric field surrounding the plasma with an antenna probe. As an analyte elutes from the chromatograph, the change in the magnitude of the electric field is dependent on the amount of analyte present.

A Michelson interferometer using a 5‐mW He–Ne laser can either be used in a photodiode detector mode to resolve transient fringe shifts ≲10−4 fringe or in a streak mode to obtain entire nanosecond resolved density profiles in a single shot. Extreme sensitivity is achieved by avoiding most noise sources. The effects of plasma light and of ray deflection due to density gradients are compensated for by the use of a lens, stop, and filter combination. Vibration induced signals are nearly eliminated by the use of feedback stabilization. A differential light detector system which subtracts signals at opposite sides of a fringe protects against laser noise and other spurious signals while doubling the sensitivity. In the streak mode a cylindrical lens beam expander allows utilization of nearly all of the laser light.

Experimental results on the collective acceleration of ions using a relativistic electron beam (0.5 MeV, 30 kA, 60 ns) are presented. A gas cloud consisting of either H2, He, or N2 gas was used as the ion source. Ion species, charge state, and energy were measured. Ions were accelerated as derived from the hydrogen and helium gas sources but not from the nitrogen gas source. In almost all shots significant numbers of hydrogen and carbon impurity ions were accelerated. The electron beam exhibited asymmetric propagation characteristics in the region immediately downstream from the anode.

An intense relativistic electron beam (0.5 MeV, 30 kA, 60 ns) was used for the collective acceleration of ions from (1) a localized gas ion source and (2) a localized plasma ion source. The ion energy scaling as a function of ion mass and charge state was found by using a Thomson spectrometer. Peak ion energy depended very weakly on ion mass and was independent of ion charge state. Although the presence of the ion source was necessary for ion acceleration to occur, generally the ion source did not supply the bulk of accelerated ions as many impurity ions were present.

We report on a solid‐state dispersive line frequency diagnostic circuit used in a short‐pulse (50 ns), high‐power microwave relativistic magnetron experiment. The dispersive element of the circuit consisted of an epitaxial yttrium iron garnett film upon which magnetostatic surface waves were launched transverse to the bias magnetic field. By varying the bias field from 200 to 1000 Oe, the circuit passband could be varied throughout the 2–5‐GHz region of interest with an accompanying variation in the bandwidth from 1000 to 450 MHz, respectively. The nonlinear dispersion, which could also be varied by changing the bias field, was measured using both phase data and pulsed techniques. The results of magnetron frequency measurements at 3.1 and 4.3 GHz using both the dispersive line and a heterodyne circuit are compared. An agreement of 1% was achieved when the heterodyne output was Fourier analyzed and the dispersive line measurements were digitized and related to the pulsed calibration results.

Low density plasma-double gridded antenna system for ion and electron signal propagation studies, observing multiple reflections of acoustic and ballistic pulses and bulk phenomenon

An argon annular puff‐gas z‐pinch has been experimentally investigated during the early phase of the current pulse using a magnetic flux probe and streak interferometry. The current is seen to follow the flared outer edge of the gas jet and to be returned primarily at axial positions z

A fast response magnetic loop current monitor has been developed to measure relativistic electron beam return currents. The monitor has a rise time of about a nanosecond and a high degree of symmetry with moderate sensitivity, variable from about 1 to 10 V/kA. This simple monitor, with a thickness of 0.254 mm or less, is thin enough to be placed between segments of return current path in the diode or drift tube regions, is insensitive to flashover, beam and plasma bombardment, and radiation effects, and measures net current, thus offering some advantages over conventional magnetic probes, since the main components are outside of the vacuum region. Design criteria, an equivalent circuit analysis, and typical calibration waveforms are presented. Experimental current measurements for a pinched electron beam diode configuration using both conventional magnetic probes and ''gasket-type''current monitors with the FX-75 relativistic electron beam accelerator are presented.

The disclosure relates to an apparatus for producing pulsed and intense relativistic electron beams which by means of linear pinch techniques are focused down to less than 2 mm diameter and preferably less than 1 mm, thereby making possible the generation of an extremely high power density on a selected target. The beams are approximately 30-nsec with a current of 40 ka when 3.5 million volts are applied to the cathode. The disclosure is also concerned with an apparatus providing for the impingement of such beams upon targets which are adapted to make possible the production of thermonuclear fusion power and the production of transuranic elements in more than microgram quantities.

An easy‐to‐fabricate, conical, annular supersonic nozzle has been developed for use in high‐power, puff gas z‐pinch experiments. A fast responding conical pressure probe has also been developed as an accurate supersonic gas flow diagnostic for evaluating the transient gas jet formed by the nozzle. Density profile measurements show that the magnitude and radial position of the gas annulus are fairly constant with distance from the nozzle, but the gas density in the center of the annulus increases with distance from the nozzle.