EXPERIMENTAL MEASUREMENTS OF CHARACTERISTICS OF NORMAL IONIZING SHOCK WAVES

A cylindrical shock tube has been used to study normal ionizing shock waves propagating, parallel to a steady axial magnetic field, into hydrogen gas at a neutral pressure of 100 m torr. The shock velocity and post-shock parameters such as magnetic and electric fields, particle density and electron temperature are compared with theoretical calculations of these quantities obtained from the conservation equations and a modified form of the Chapman-Jouguet hypothesis. For the purposes of this calculation it was assumed that the Saha equation was applicableo the plasma. Over a range of steady axial magnetic fields from 0.65 to 12.5 kgauss and discharge currents from 20 to 160 ka, good agreement has been obtained between theory and experiment for shock velocities and for electric fields both behind and ahead of the shock. Density measurements display the predicted theoretical trend, but the measured compression ratios across the shock are low, implying a loss of particles during the ionizing process.