A single-fluid, one-dimensional, time-dependent model of an unconfined plasma armature is discussed. The temporal evolution of the pressure and current density distributions is shown to be controlled by a combination of magnetic diffusion, shear, ablation, and magnetoacoustic wave propagation within the plasma. Different parameter regimes are explored, and the characteristic time constants and length scales are established for these various physical processes. It is shown that, when the plasma slip-velocity is low, the plasma may fragment or disperse by virtue of a diffusion-driven instability. Conversely, when ablation is high and the slip-velocity is large, the plasma will form a parasitic current sheet at the tail of the armature, which may detach from the primary plasma. The first of these instabilities is initiated by a decrease in the input current. The second occurs above a certain critical combination of magnetic field strength and ablation coefficient


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    Title :

    The electrodynamics of railgun plasma armatures


    Additional title:

    Die Elektrodynamik der Plasma-Armatur einer schienengebundenen Abschußvorrichtung


    Contributors:


    Publication date :

    1991


    Size :

    4 Seiten, 4 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English




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