Download or read book Stable Propagation of a High current Electron Beam written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies of self-focused, high-current electron-beam propagation phenomena are compared with the results of computational modeling. The model includes the radial structure of the beam-plasma system, a full electromagnetic field description, primary and secondary gas ionization processes, and a linear theory of the hose-like distortions. Good agreement between the experimental results and the computations strengthens the premise that hose instability is the principal limitation to propagation at high pressure.
Download or read book Stable Propagation of an Electron Beam in Gas written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conditions for the stable propagation of a pinched electron beam in low pressure gas (p approximately 0.1 to 100 torr) are described. The observed window of good propagation around p approximately 2 torr air is interpreted as the quenching of the two-stream mode by sufficiently high plasma density and collision frequency, and the simultaneous suppression of the resistive hose mode by sufficiently rapid generation of electrical conductivity from breakdown ionization.
Download or read book Beam Propagation Study Stabilization of the Resistive Hose Instability in Intense Electron Beams written by R. J. Adler and published by . This book was released on 1984 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of experiments has been performed to investigate the effect of unidirectional beam particle rotation on the resistive hose instability. Using the 4 MV, 100 kA, IBEX accelerator in a foil diode configuration, hose growth for hollow, partially hollow, and non-rotating Bennett profile beams was investigated. We found that partially hollow, rotating beams were most stable. In particular, they were more stable than non-rotating Bennett profile beams both in terms of the growth rate in per cm and in the growth per betatron wavelength. The observed reduction in instability growth rate per betatron wavelength over Bennett profile beams was a factor of 2.5. Stable propagation for>6 betation wavelength (the full experiment length) was observed in some shots where the beam was well aligned. Broadened return current profiles and long plasma decay times were also observed, consistent with our present understanding of high current mode propagation.
Download or read book Studies of High Current Relativistic Electron Beam Propagation written by David Andrew Hammer and published by . This book was released on 1969 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Energy Physics Facilities written by United States. Congress. House. Committee on Science and Technology. Subcommittee on Energy Development and Applications and published by . This book was released on 1984 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Beam Propagation Experimental Study written by C. A. Ekdahl and published by . This book was released on 1981 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pressure regime for stable propagation of an intense relativistic electron beam (I> 20 kA, W> 1.5 MeV, t> 20 ns) was determined and the beam-current density distribution was measured using an array of fast-response, subminiature Faraday cups. Experiments were performed on the stabilization of this pre-equilibrated beam when it was extracted into full-density air. (Author).
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-11 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fusion Energy Update written by and published by . This book was released on 1982-04 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Propagation of high current relativistic electron beams written by D. A. Hammer and published by . This book was released on 1969 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pinched Propagation of High Power Pulsed Electron Beams for Welding and Materials Processing Applications written by and published by . This book was released on 1994 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron beams are used commercially as intense heating sources for welding and related materials processing applications. The beams used for welding operate continuously with energy up to 200 keV and current - 1 A. Because these beams are severely degraded by propagation in air over any substantial range, most present-day electron-beam welders require vacuum pumping and precision focusing, which has severely restricted utilization of the technology. Over the past few decades, a different class of electron-beam generators has been developed that produces pulsed beams with energies of several MeV, currents of 1 kA or more' radii as small as 1 mm, pulse lengths of tens of ns, and pulse repetition rates up to several kHz. We show here that beams of this type can propagate in ambient air, in a tightly pinched mode and with acceptable stability, over distances of a few tens of cm We determine the constraints on the choice of beam parameters, due mainly to the effects of gas scattering and the resistive instability. We show that stability can be enhanced, and the acceptable parameter range extended considerably, by using a narrow conducting pipe filled with air or another gas to guide the beam to the workpiece. Relativistic electron beam, Nordsieck, Welding, Material processing, Resistive hose instability.
Download or read book Soviet Research on the Transport of Intense Relativistic Electron Beams Through High pressure Air written by Nikita Wells and published by . This book was released on 1987 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soviet research on the propagation of intense relativistic electron beams (IREB) through fairly high-pressure air (pressure range 0.1 to 760 Torr) since the early 1970s has included the study of the plasma channel created by the passage of the electron beam through air, the resistive hose instability and its effect on beam propagation, the effect of self-fields, current enhancement, gas expansion, return currents, inherent beam energy spread, and other factors. This report covers Soviet developments in IREB propagation through air where the beam is not focused by external magnetic fields. The information was obtained from Soviet open-source publications with emphasis given to the last ten years of beam propagation in the Soviet Union. The volume of papers published on this subject in recent years indicates a significant increase in Soviet research in this area.
Download or read book Studies in High Current Beam Propagation at Reduced Pressures written by E. R. Parkinson and published by . This book was released on 1985 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hall current effects in the redistribution of plasma currents and possible stability enhancement in electron beams were explored in a range of pressure regimes. Improved e.m. algorithms and conductivity models were developed as part of the studies. Substantial effects were found below a low pressure threshold, where nonlocal effects, non-Ohmic conductivity, and a highly non-Maxwellian distribution of plasma electron energies were all found to contribute significantly to the magnitude of Hall current phenomena. Several e.m. field algorithms were developed for application to the nonlinear hose-displacement regime. An iterative approach to the solution of the modally expanded field equations was found to yield fast and accurate solutions.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Beam Propagation in the Ion Focused Regime IFR with the Experimental Test Accelerator ETA written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The IFR is a well-known stable, low pressure (0.10 to 0.120 torr in air) propagation window. Secondary electrons created by collisions of beam electrons with gas atoms are rapidly expelled by the strong radial electric field of the beam charge. The ions that remain inside the beam partially neutralize the electric field, allowing magnetic pinch forces to focus the beam. Experiments with the ETA beam have re-verified this stable window and are reported. Image forces from a close wall IFR propagation tank are also experimentally shown to center the beam and damp transverse oscillations. Results of experiments using 5 and 15 cm dia beam tubes are reported. For p tau> 2 torr-nsec (gas pressure x time into pulse the beam charge becomes completely neutralized by the ions, allowing a build up of plasma and resultant beam-plasma instabilities. The onset of these instabilities has been measured using rf pickup loops (0 to 2 GHz) and microwave detectors (6 to 40 GHz), and are also reported.
Download or read book FY US Air Force Plan for Defense Research Sciences written by and published by . This book was released on 1986 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plasma Physics Index written by and published by . This book was released on 1982 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1977 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
