Sixteen frame interferometer for a study of a pinch dynamics in PF-1000 device

Full text of publication follows: Plasma-Focus (PF) is a very intense neutron-producing device. The scaling law for the neutron yields formulated at the beginning of the plasma focus investigations was very promising for these devices. However, investigations carried out on MJ devices suggested that there is a certain condenser energy limit above which the scaling law is not valid. Hence the essential problem to be resolved in PF research has always been to discover the physics, which dominates the configuration, a question closely related to the neutron production mechanism and plasma evolution. To study the evolution of the plasma a laser interferometer with exposure times of about 1 ns, were employed. The beam of diagnostic laser of 527 nm wavelength was optically split in 16 beams with a different time of incident with plasma in the range from zero to 220 ns.These features of the diagnostic equipment enabled the detailed study of the pinch density evolution with high temporal and spatial resolution. On the basis of the plasma images, the dynamics of the plasma sheath, characteristics periods of the plasma evolution and plasma dimensions were determined. In order to reconstruct the spatial distribution of the electron density a special mathematical method was prepared. The 16 frames Mach-Zehnder interferometer has established on PF-1000. The interferometer is able to register whole pinch evolution of MJ device (220 ns) in one shot. So, we have opportunity to correlate neutron emission with a pinch plasma evolution with a well accuracy. The paper reports on the design of a 16 frames Mach-Zehnder interferometer established on MJ Plasma-Focus device and interferograms obtained during the last experimental sessions. (authors)