Z- pinch dynamics from the generalized Bennett relation

The plasma virial theorem is derived from the equation of mass motion and evaluated for rotationally field-symmetric configurations so as to yield a general dynamic Bennett relation. The acceleration term is formulated in different ways. Magnitudes of expansional and compressional terms are discussed. The relation extends the recent Baker-Phillips result that magnetic field diffusion has a deconfining action in the late stage of $z$ pinching.