ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Beam-generated plasmas for processing applications : The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 2558-2564 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The use of moderate energy electron beams (e-beams) to generate plasma can provide greater control and larger area than existing techniques for processing applications. Kilovolt energy electrons have the ability to efficiently ionize low pressure neutral gas nearly independent of composition. This results in a low-temperature, high-density plasma of nearly controllable composition generated in the beam channel. By confining the electron beam magnetically the plasma generation region can be designated independent of surrounding structures. Particle fluxes to surfaces can then be controlled by the beam and gas parameters, system geometry, and the externally applied rf bias. The Large Area Plasma Processing System (LAPPS) utilizes a 1–5 kV, 2–10 mA/cm2 sheet beam of electrons to generate a 1011–1012 cm−3 density, 1 eV electron temperature plasma. Plasma sheets of up to 60×60 cm2 area have been generated in a variety of molecular and atomic gases using both pulsed and cw e-beam sources. The theoretical basis for the plasma production and decay is presented along with experiments measuring the plasma density, temperature, and potential. Particle fluxes to nearby surfaces are measured along with the effects of radio frequency biasing. The LAPPS source is found to generate large-area plasmas suitable for materials processing. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1345506
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Theory and simulation of ion noise in microwave tubes (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 297-320 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Since there is always some ambient gas in electron beam devices, background ionization is ubiquitous. For long pulse times, the electrostatic potentials associated with this ionization can reach significant levels and give rise to such observed phenomena as phase noise in microwave tubes. This noise is usually associated with the motion of ions in the device; therefore, it is called ion noise. It often manifests itself as a slow phase fluctuation on the output signal. Observations of noise in microwave tubes such as coupled-cavity traveling wave tubes (CC-TWTs) and klystrons have been discussed in the literature. In this paper, a hybrid model is discussed in which the electron beam is described by the beam envelope equation, and the ions generated by beam ionization are treated as discrete particles using the one-dimensional equations of motion. The theoretical model provides good qualitative as well as reasonable quantitative insight into the origin of ion noise phenomena. The numerical results indicate that the model reproduces the salient features of the phase oscillations observed experimentally. That is, the scaling of the frequency of the phase oscillations with gas pressure in the device and the sensitive dependence of the phase oscillations on the focusing magnetic field. Two distinct time scales are observed in simulation. The fastest time scale oscillation is related to the bounce motion of ions in the axial potential wells formed by the scalloping of the electron beam. Slower sawtooth oscillations are observed to correlate with the well-to-well interactions induced by the ion coupling to the electron equilibrium. These oscillations are also correlated with ion dumping to the cathode or collector. As a practical matter, simulations indicate that the low frequency oscillations can be reduced significantly by using a well-matched electron beam propagating from the electron gun into the interaction circuit. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1329153
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Production of large-area plasmas by electron beams : The 39th annual meeting of division of plasma physics of APS (1998)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 2137-2143 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An analysis is presented for the production of weakly ionized plasmas by electron beams, with an emphasis on the production of broad, planar plasmas capable of reflecting X-band microwaves. Considered first in the analysis is the ability of weakly ionized plasmas to absorb, emit and reflect electromagnetic radiation. Following that is a determination of the electron beam parameters needed to produce plasmas, based on considerations of beam ionization, range, and stability. The results of the analysis are then compared with a series of experiments performed using a sheet electron beam to produce plasmas up to 0.6 m square by 2 cm thick. The electron beam in the experiments was generated using a long hollow-cathode discharge operating in an enhanced-glow mode. That mode has only recently been recognized, and a brief analysis of it is given for completeness. The conclusion of the study is that electron beams can produce large-area, planar plasmas with high efficiency, minimal gas heating, low electron temperature, high uniformity, and high microwave reflectivity, as compared with plasmas produced by other sources. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.872886
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Stable single mode operation of a quasioptical gyrotron (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 419-426 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The regions in parameter space of stable single mode operation of a quasioptical gyrotron are determined theoretically for a number of configurations. A pencil beam is found to give rise to large operating regimes where single mode operation is stable. These regions shrink dramatically when an annular beam is considered. However, stable operation can be restored by slightly tilting the axis of the cavity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    High peak power Ka-band gyrotron oscillator experiment (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 2226-2238 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A Ka- band gyrotron oscillator powered by a 600 kV pulse-line accelerator has produced approximately 100 MW at 35 GHz in a circular TE62 mode. It has also demonstrated frequency tuning over the range 28 to 49 GHz by operating in a family of TEm2 modes, with the azimuthal index m ranging from 4 to 10, by variation of the guide magnetic field. Operation is in general agreement with the predictions of theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866157
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Nonlinear analysis of a magnicon output cavity (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 3045-3055 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A nonlinear analysis of the wave–particle interaction in the output cavity of a frequency-doubling magnicon amplifier is presented. The cavity is immersed in an axial magnetic field, wherein electrons interact with a rotating TM210 mode via a gyroresonant mechanism. The electron equations of motion and the wave equation for the radio-frequency (rf) field are derived and expressed in terms of scaled variables in order to study the general scaling of the output cavity. Single-electron, time-dependent simulation of the interaction in the cavity is performed to assess the accessibility and stability of high-efficiency states for an X-band magnicon. Results from multielectron, steady-state simulation are presented to show the effect of spreads in electron-beam radius, energy, and transverse momentum on the efficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860691
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Megavolt, multikiloamp Ka band gyrotron oscillator experiment (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 193-198 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A Ka-band gyrotron oscillator experiment using a 1–1.35 MeV, multikiloampere beam from a pulse line accelerator has produced approximately 250 MW at 35 GHz in a circular TE62 mode with a peak efficiency exceeding 10%. Time-dependent simulation studies have been used to predict the behavior of a high-peak-power, short-pulse gyrotron in this parameter range. The simulations demonstrate the occurrence of such phenomena as hard excitation of the gyrotron as a result of the time dependence of the voltage pulse. The experimental results are in reasonable agreement with the predictions of theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859527
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Operating characteristics of a continuous-wave-relevant quasioptical gyrotron with variable mirror separation (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 1046-1056 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Results from a quasioptical gyrotron experiment with a 20–28 cm mirror separation are presented, showing operation at powers up to 150 kW and efficiencies up to 12%. The output coupling would be varied from 0.4%–3% by changing the mirror separation and operating frequency. Operation was obtained over frequencies ranging from 95–130 GHz by changing the axial magnetic field, limited on the low end by waveguide cutoff in the diagnostics and at the high end by the maximum magnetic field achievable. The output power varied by approximately a factor of 2 over this range. Frequency variation of 4% was achieved by varying only the electron gun voltage; however, the output power also varied substantially due to the fact that the electron beam power was changing dramatically. Efficiency optimization by variation of output coupling and tapering of the magnetic field has been demonstrated. Regions of single-mode operation at powers up to 125 kW have been characterized and compared to recently developed theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859278
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Raman sidescattering in laser-produced plasmas (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 3409-3413 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The theory of the Raman sidescattering instability in an inhomogeneous plasma is revisited. The growth rate is found from the eigenvalue of a second-order ordinary differential equation in the Fourier domain. Under certain, rather easily satisfied constraints, the normalized growth rate depends on a single parameter involving laser strength, gradient scale length, and resonant density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865341
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Spontaneous radiation of an electron beam in a free-electron laser with a quadrupole wiggler (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1584-1590 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A calculation is presented of spontaneous radiation emitted by an electron beam passing through a continuously rotating quadrupole magnetic undulator. It is shown that radiation spectrum emitted in forward direction of beam propagation has four peaks, corresponding to four betatron frequencies. Utilizing the Madey theorem, a stimulated emission is calculated and presented as gain versus frequency curves, for different values of the quadrupole magnetic field. A free-electron laser operating at two or three radiation frequencies with a quadrupole magnetic wiggler is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337295
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...