Thetatron discharge study

O-pinch combined with Z-pinch has been used for this course of study. Diagnostic tools used in this study are Rogowsky coil, voltage divider, magnetic probes, double electric probe, micro wave detector, plastic scintillation detector and spectroscopy. The measurements have been performed with helium gas pressure of 2 x 10-1 mbar. The discharge current was 22.5 kA for bank charging voltage of 9 kV. It has been found that the plasma sheath is formed near the discharge tube walls and the plasma sheath starts to move towards the axis. The sheath motion is in agreement with snow plow model. The plasma sheath motion is detected by a magnetic prob. It has been found that, the plasma sheath radial velocity has a maximum value= 1.8 x 106 cm /sec in range from r=3 cm to r =1.9 cm from the tube wall. After this, the velocity is decreased until it reaches a minimum value=0.3 x 106 cm/sec r = 1.1 cm . The plasma electron temperature has been evaluated at p 2 x 10-1 mbar at the center of the plasma tube by using relative lines intensity. The electron temperature T is equal to 4.5 eV. Double electric prob measurements show that the electron temperature T is 4.65 eV with density of 3.36x1012 cm-3. Trapped axial and radial magnetic fields have been measured by a magnetic probe. It has been found that the axial and radial trapped magnetic fields are increased linearly with discharge current, and the axial trapped magnetic field decreases with gas pressure according to the relation Bt= log P + C where C is constant and α = -1.3. 3.19 figs., 39 refs