Search Results - (Author, Cooperation:G. B. Crew)

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  1. 1
    Staff View
    Publication Date:
    2016-01-20
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Johnson, Jay R. ; Chang, Tom ; Crew, G. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7674
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Linear mode conversion is considered between the ion-cyclotron and magnetosonic branches in a multispecies plasma with parallel magnetic field gradients. The results are interpreted in terms of ion conic heating. The mode-conversion coefficients are solved using perturbation theory, a phase integral approach, and saddle-point theory. These results are compared with numerical calculations. The coefficients thus obtained demonstrate that substantial coupling occurs between the four propagating modes, and a definite absorption occurs. Such absorption corresponds to ion heating and is, under realistic circumstances, sufficient to explain the outflow and heating of ionospheric oxygen. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.871339

    Articles: DFG German National Licenses
  3. 3
    Crew, G. B. ; Chang, T. S.

    [S.l.] : American Institute of Physics (AIP)
    Published 1985
    Staff View
    ISSN:
    1089-7666
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The formation of ion conics is discussed in terms of a model which permits an asymptotic determination of the ion distribution function. This model is applicable to a class of observed ion conic events where the ion energization is attributable to lower hybrid wave activity. A two-stage process is considered wherein the upward moving component of the ambient ion population is first subjected to a region of weak turbulence and is then allowed to drift adiabatically up the geomagnetic field. Identification of the ratio of ion thermal speed to mean wave speed as a small parameter leads to a uniformly valid solution of the quasilinear diffusion equation. The resulting analytic form for the ion conic is then available for further analytic work. Implications and limitations of the model will be discussed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.865244

    Articles: DFG German National Licenses
  4. 4
    Crew, G. B. ; Chang, Tom

    [S.l.] : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1089-7666
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A description of the generation and evolution of ionospheric oxygen ion conic distributions by electromagnetic ion cyclotron resonance heating is formulated in terms of a path integral. All of the relevant physics is contained in this path integral, which may be used to calculate measurable properties of the conic distribution. Although the presentation is applied to this specific ionospheric context, the treatment may be generalized to treat other diffusion problems of interest.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.866907

    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    1476-4687
    Source:
    Nature Archives 1869 - 2009
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Notes:
    [Auszug] Gamma-ray bursts (GRBs) fall into two classes: short-hard and long-soft bursts. The latter are now known to have X-ray and optical afterglows, to occur at cosmological distances in star-forming galaxies, and to be associated with the explosion of massive stars. In contrast, the distance scale, ...
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1038/nature04213

    Articles: DFG German National Licenses