Arc Phenomena and Gasdynamic Effects due to Interaction of Shock Waves with Magnetic Fields II

The already published first part of this paper1 described arc phenomena and gasdynamic effects produced by interaction of shock-heated plasma flow with a magnetic field perpendicular to the flow direction. Currents of density j flowed through electrodes flush mounted on the inside of the shock tube and connected on the outside. The plasma wras therefore subjected to retarding j X B forces directed opposite to the velocity v and was slowed down. The strong reduction of the plasma velocity resulted in secondary gasdynamic effects, such as reflected shock waves. The high currents necessary for strong interaction could only be produced in the form of arcs. On the other hand, it is known from the literature that only one-dimensional flow has been investigated theoretically because of the mathematical difficulties. With arcs it is difficult to satisfy the simple conditions of one-dimensional theory, such as uniform current distribution in the interaction region. In order to achieve an approxi­ mately uniform current distribution in the interac­ tion volume the arc phenomenon was utilized by mounting many electrodes of small surface area alongside and behind one another and shortcircuiting the pairs separately, thus producing many arcs alongside and behind one another. The magnetic field was produced with a crowbarred capacitor bank via coils. The maximum magnetic field strength was about 7 kG. This restricted the maximum interaction strength. The observed gasdynamic effects included reflected shocks still running in the interaction region. This second part of the paper describes results obtained with the same apparatus, but with a stronger magnetic field above 20 kG that was pro­ duced with electromagnetic field coils. With higher