A theta pinch with 0.23-torr deuterium, 60-kG peak magnetic field and 1.8 μsec half cyclo has been further investigated. Three cases were observed: initial bias field of (a)zero, (b)+2kG, (c)—2 kG. For the interpretation of plasma phenomena one has to take into account non-stationary processes due to the ends. With —2 kG the usual axial contraction and heating rates of 1 keV/μsec were found. Both the incident and reflected axial shocks were measured, and they did not cause the trapped field to disappear or significantly increase the plasma radius even though the density increased by 2. With +2kG, β is a few per cent, and the plasma follows the field lines. Here Te < 80 eV. With zero field a rarefaction wave rims into the plasma causing a density increase by 2 and plasma diameter decrease. With zero field and —2 kG electron temperatures were comparable indicating that diffusion heating is also important in high- β cases (β ≈ 0.8). The x-ray and optical plasma radii agree within 1 mm. When one compares the time dependences of Te and ne it becomes questionable whether the soft x rays used for the determination of Te are thermal or not. With zero and —2-kG fields, discharge cleaning reduced impurities to ⪅ 0.1o,o, and the reverse field and relatively high β, respectively, persisted through the entire half cycle. The usual abrupt reverse-field disappearance was observed with a few per cent impurity.