First steps towards a theory of the Dense Plasma Focus: Part-I: Kinematic framework with built-in propagation delay and nonzero thickness of dense sheath for generalized electrode geometry (2211.16775v1)

Abstract: This paper, Part I of a series, describes a kinematic framework for the theory of a Dense Plasma Focus which is very similar to the GV model in spirit but which differs in its scope in four respects. First, the GV model derives most of its results from the mathematical properties of the solution of a certain partial differential equation derived from assumptions that apparently represent conservation of momentum but are not a rigorous application of the relevant physics. The present model is based on the scaling properties of the standard equations of motion, which lead to mathematical results identical with the GV model. Second, the GV model is purely kinematic in nature. The present model is also kinematic like the GV model but it incorporates additional insights borrowed from other physical theories, models and experiments. Third, the GV model does not take into account the experimentally observed delay between the start of current and start of plasma propagation and the existence of a nonzero thickness of the dense plasma sheath. The present model incorporates both these features in its kinematic structure. Fourth, the unlike the GV model, the present model allows considerations of some modifications of standard Mather type geometry. In addition to the current waveform, the proposed model reproduces the height and radius of the pinch column, the ratio of pinch density to fill density, the general appearance of the umbrella like plasma profile and streak picture and formation of bounded 3-dimensional plasma structures embedded within the pinch plasma without taking into account microscopic details of physical phenomena