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
    Experimental investigation of particle heating in a strongly coupled dusty plasma (2000)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 7 (2000), S. 3904-3911 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Highly charged dust particles in a plasma can be strongly coupled when their kinetic temperature is low. This temperature is determined by a balance of heating and gas cooling. The heating is believed to be electrostatic, although its exact nature is still under investigation. Experiments in a multiple-layer plasma crystal were conducted to test proposed heating mechanisms. A method for measuring small-amplitude, low-frequency fluctuations in ion density was developed and, using this, very low-frequency electrostatic fluctuations were found upstream of the particles. These fluctuations should propagate with the ions towards the particles and heat them. However, the fluctuations were uncorrelated with, and too weak to account for, the observed particle temperatures. In the experiment, the temperature increased and then decreased with gas pressure; this result is only partly consistent with an ion wake heating mechanism. These negative findings help narrow the range of possible explanations for the observed temperatures. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1286988
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Experimental observation of very low-frequency macroscopic modes in a dusty plasma (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 1212-1219 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Images of a cloud of grains in a dusty plasma reveal a pair of very low-frequency modes, termed here the filamentary and great void modes. The plasma was a radio-frequency discharge formed between parallel-plate graphite electrodes. A cloud of 100 nm carbon particles was produced by accretion of carbon atoms produced by sputtering the graphite. The cloud was illuminated with a laser sheet and imaged with a video camera. The great void mode was a spoke-shaped region of the cloud that was free of dust and rotated azimuthally in the discharge. The filamentary mode had the appearance of turbulent striations, with a smaller amplitude than the great void. The filamentary mode sometimes appeared as a distinctive vortex, curling in the poloidal direction. Both modes had a very low frequency, on the order of 10 Hz. Two possible causes of the modes are discussed. The low phase velocity of the modes may be consistent with a dust-acoustic wave. Alternatively, the great void may be an ionization wave that moved the dust about, since a modulation in the glow was seen moving at the same speed as the void. It is argued that existing theories of waves in dusty plasmas assume weakly collisional plasmas, which may be unsuitable for explaining experimental results in laboratory dusty plasmas, since they are often strongly coupled. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871745
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Acoustic modes in a collisional dusty plasma (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 741-750 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The acoustic modes in a collisional dusty plasma are studied, taking into account the influence of ion–neutral collisions, ion drag, and neutral friction. It is assumed that the frequency of ion–neutral collisions is greater than the frequency of ion–dust collisions. Two limiting cases of short-wavelength and long-wavelength modes are considered separately, depending on the ratio of the dust–ion acoustic frequency to the frequency of ion–neutral collisions. It is shown that for the long wavelengths coupling between the modes becomes strong, causing the appearance of the hybrid long-wavelength mode. It is also found that in the long-wavelength case there are two types of instability caused by ionization. The theoretical results are compared with the data obtained in experiments with growing particles. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873311
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Saturation broadening of laser-induced fluorescence from plasma ions (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 996-1000 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Saturation broadening is an obstacle in using laser-induced fluorescence as a plasma diagnostic. The Doppler-broadened line shape ideally yields the ion velocity distribution function, but at high laser power, saturation of the optical transition leads to additional undesirable line broadening. We test three different prescriptions for plasma experimentalists to avoid saturation broadening while maintaining a strong signal. Based on experiments in an argon plasma, and a semiclassical atomic physics simulation, we have identified the prescription that is the easiest to use and the least sensitive to the spatial profile of the laser beam. This procedure is to measure the laser intensity that leads to saturation on the peak of the spectral line, and then to reduce the intensity to 20% of the saturation level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Double lock-in detection for recovering weak coherent radio frequency signals (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 1662-1664 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A single radio frequency lock-in amplifier reduces broadband noise, but not rf pickup of the same frequency as the signal. If this pickup noise is at least 14 dB stronger than broadband noise, after both have passed through the lock-in, then the signal-to-noise ratio can be improved by applying the lock-in output to a second, low-frequency lock-in which is synchronized to an independent modulation of the signal. Weak coherent radio frequency signals buried in both rf pickup and broadband noise can be recovered by using this double lock-in method, as demonstrated in a plasma diagnostics experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138121
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Comment on "Optical carriage for laser-induced fluorescence in a magnetized plasma'' [Rev. Sci. Instrum. 59, 2306 (1988)] (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 3830-3831 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Anderegg et al. use a multimode optical fiber to transport their laser beam to a plasma for laser-induced fluorescence (LIF) experiments. While this method of laser light transportation is convenient, it is not suitable for all experiments. Experimenters considering using a multimode fiber should be aware of two undesirable complications that result from interference between various guided modes. First, for the measurement of the Doppler broadened line shapes, interference patterns may introduce undesirable inhomogeneous saturation line broadening. Second, for broadband ion density measurements, bending the fiber varies the interference pattern which alters the effective observed volume yielding unpredictable changes in the measured signal strength, particularly when the experiment requires high spatial resolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140453
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Magnetic field dependence of sputtering magnetron efficiency (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 1052-1054 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A Monte Carlo simulation of electron transport is used to predict the dependence of the ionization efficiency on the magnetic field strength of a planar magnetron. This offers insight into the operation of the magnetron, and it also provides two valuable practical results. First, the efficiency increases with field strength only up to a saturation level. Operating a magnetron with a stronger field strength would only lead to an undesirable loss of target utilization. Second, a scaling law is found that is useful for designing magnetrons of different sizes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106342
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Observation of the backward electrostatic ion-cyclotron wave (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 2845-2847 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The backward branch of the electrostatic ion-cyclotron wave has been observed for the first time. The wave, which was driven by a phased antenna structure inserted in a neon plasma, exists in the parameter ranges 2Ti/mi(very-much-less-than)(ω/k(parallel))2(very-much-less-than)2Te/me, nΩi〈ω〈(n+1)Ωi, Te(approximately-greater-than)Ti, and ωpi〉Ωi. Double-tip probe interferometry data agree with the theoretical dispersion relation. The antenna couples into the wave more readily on the side of the antenna where it has its smallest wavenumber.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Collisional plasma sheath model (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2796-2804 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of ion collisionality on the plasma sheath are revealed by a two-fluid model. In contrast to previous work, the ion–neutral collision cross section is modeled using a power law dependence on ion energy. Exact numerical solutions of the model are used to determine the collisional dependence of the sheath width and the ion impact energy at the wall. Approximate analytical solutions appropriate for the collisionless and collisionally dominated regimes are derived. These approximate solutions are used to find the amount of collisionality at the center of the transition regime separating the collisionless and collisional regimes. For the constant ion mean-free-path case, the center of the transition regime for the sheath width is at a sheath width of five mean-free paths. The center of the transition regime for the ion impact energy is at a sheath width of about one-half of a mean-free path.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859987
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Laser-induced fluorescence characterization of a multidipole filament plasma (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2913-2921 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A multidipole filament discharge was characterized using sub-Doppler laser-induced fluorescence (LIF). The ion temperature was found to be Ti=0.028±0.007 eV, measured in the center of an argon discharge. This stands in contrast to the much higher ion temperatures, 0.2〈Ti〈0.5 eV, reported by researchers using gridded electrostatic energy analyzers. The discrepancy is attributed to the energy resolution of the detectors, with the LIF providing more accurate measurements. In another result, the metastable excited-state ion density was found to scale linearly with the electron density and the discharge current under most conditions. This experiment also demonstrates that LIF can be used for basic plasma physics research in multidipole discharges.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859924
    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...