This paper (paper I) presents the first part of results obtained with the PF-1000 facility for the first time at its upper energy limit (≈1 MJ). Special attention is paid here to plasma (‘pinch’) dynamics, which was investigated in relation to its electro-technical and radiation (especially neutron) characteristics with the help of a number of diagnostics, both time-integrated and with nanosecond temporal resolution. In these methods we utilized a Rogowski coil for the routine electro-technical measurements, visual multi-frame and streak cameras, soft x-ray pin-hole multi-frame cameras, PIN-diode assembly and PM tubes with scintillators for soft and hard x-rays as well as for neutron investigations together with a set of activation counters. In particular, the temporal cross correlation of different phenomena taking place during the discharge was investigated. The pinch's longevity appears to be 10–15 times larger than the ideal magnetohydrodynamic growth time (ratio of the pinch radius to the ion thermal velocity). It is demonstrated how the ‘target’ dynamics (pinch plasma of the dense plasma focus (DPF)) depends on and may be controlled by the electrode's size and the geometry of the chamber in this large-scale device. Diffraction of a shock wave together with a current sheath on an obstacle made at the DPF anode cap opens an opportunity for an inertial electrode to be used in future at larger DPF devices.

In order to investigate the Plasma-Focus (PF) pinch dynamics within the large PF-1000 facility the use was made of fast streak-and frame-cameras operated as the routine optical diagnostic tools. They enabled images of a current-sheath (CS) layer and the PF-pinch to be recorded within the visible range (VR) at chosen instants of the investigated PF-discharges. The measurements were carried out end-and side-on the PF-1000 electrode system under different experimental conditions. For the temporal synchronization of both cameras with the chosen phases of the PF discharge, we used current derivative (dI/dt) waveforms and X-ray signals recorded for each shot. During the described PF-1000 experiments, we performed also other complimentary measurements. Particular attention was paid to studies of current-and voltage-waveforms of the investigated discharges, to a comparison of the total neutron yields measured by means of silver activation counters, and to the analysis of time-resolved neutron-and X-ray-signals recorded with several scintillation detectors. Results of the observations carried out with the fast streakand frame-cameras, which were compared with other experimental studies, allowed better understanding of all the PF-discharge phases to be achieved. In particular, the correlation of different quantum-and corpuscular-radiation pulses, which has influence on the total fusion-neutron yield, has been analyzed. 52.58.Lq. 52.59.Hq PACS

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show that the ion spectra can be effectively registered with this modified spectrometer. Since the ratio of the accelerated energy to the original ion energy (for single charged ions) is larger than 50, the acceleration field does not influence the spectra distribution of the ion beams notably.