Abstract The parameters and location of the weak bow shocks detected by the spaceprobes are compared with gas dynamical calculations. No shock is identifiable at times, indicating that it is not dominant over temporal changes and not very significant in enhancing intrinsic dissipation and phase mixing processes. The location at comet Halley was closer than predicted on the mass-loading model, indicating inefficient pick-up of implanted ions. Flaring of the shock limbs was also lower at the Giotto encounter, closer to the minimum level induced by strong cooling in the inner coma. The suprathermal cometary ions' disappearance in the ionosheath outside the magnetopause discontinuity confirms this. Flow deviation and shock strength need closer modelling, but the thick shock in the protons is evidence for an ion-ion instability mechanism, apart from the upstream Fermi processes.


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    Title :

    Bow shock decay in comets Giacobini-Zinner and Halley


    Contributors:

    Published in:

    Publication date :

    1986-01-01


    Size :

    4 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



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