Experimental Study of Plasma Structure in a Small Railgun

摘要

Miniature B-dot coils were used to probe the current in the plasma boundaries atboth the positive and negative rails in a small railgun. Waveforms from a row of three coils at each rail were examined for evidence of the existence of time-ordered fine structure effects within the plasma boundary. No such order was detected. However, spatially correlated effects were observed and these were attributed to rapidly changing filamentary structure in the plasma. The polarity-reversal, or cross-over characteristics, of the B-dot waveforms showed anomalous features. Possible explanations are discussed. Evidence from rail damage is presented supporting the view that the rail-plasma boundary is associated with a number of complex processes and that localized irregularities in the B-dot waveforms should be expected.