Dynamics of the Current Distribution in a Discharge of the PF-3 Plasma Focus Facility

In this paper, results are presented from studies of the dynamics of the plasma-current sheath and current distribution in the PF-3 facility, one of the largest plasma focus machines in the world. The experiments were done at input energy of $W = 290 hbox{kJ}$ and discharge current of $I sim 2 hbox{MA}$, with the chamber being stationary filled with the working gas. The current sheath parameters were measured with absolutely calibrated magnetic probes installed at different distances from the system axis and at different heights above the anode plane. The possibility is demonstrated of the formation of closed current loops due to the development of shunting breakdowns in the insulator region. The maximum residual plasma density at which the electrode gap remains magnetically self-insulated is estimated.      

Study of Momentum and Energy of Plasma Flow Generated in Plasma Focus Discharge

The paper is devoted to the study of the plasma flows generated in the plasma focus discharge at the PF-3 facility at its propagation in the ambient medium up to distances of ~100 cm and, in particular, the study of the dynamics of such important parameters as velocity, total energy, and momentum. Momentum and energy measurements were made using a ballistic pendulum, which could be used simultaneously in the calorimeter mode. Optical collimators are used to measure the flow velocity. It is shown that, in experiments with argon at a distance of 65 cm, the energy density of the incident flow of ≥10 J/cm2 is observed. The total number of particles in the flow and the total mass of the flow are calculated.     

Physicochemical properties of ceramic tape involving Ca<Subscript>0.05</Subscript> Ba<Subscript>0.95</Subscript> Ce<Subscript>0.9</Subscript>Y<Subscript>0.1</Subscript>O<Subscript>3</Subscript> as an electrolyte designed for electrolyte-supported solid oxide fuel cells (IT-SOFCs)

Energetic materials such as a mixture of guanidine nitrate (GN)/basic copper nitrate (BCN) are used as gas generators in automotive airbag systems. However, at the time of the airbag inflation, the gas generators release toxic combustion gases such as CO, NH₃, and NO_x. In this study, we investigated the combustion and thermal decomposition behaviors of GN/BCN mixture, focusing primarily on their exhaust gas composition. As a result, when the exhaust gas of the combustion under constant pressure in an inert gas stream was analyzed using a detection tube, the amount of NO_x (mainly NO) yielded greater decrease with increasing atmospheric pressure as compared to the amounts of CO and NH₃. Thus, provided GN/BCN is ignited in a closed container, a large amount of NO_x is presumed to have been released during the initial stage of combustion, which yielded comparatively low pressure. Results of the thermogravimetry–differential scanning calorimetry–Fourier transform infrared spectroscopy (TG/DSC/FTIR) indicated that the GN/BCN mixture caused endothermic decomposition at 170 °C and exothermic decomposition at 208 °C, which was accompanied by 66% mass loss. The decomposition gases, CO₂, N₂O, and H₂O, were detected via FTIR spectrum. Because N₂O was not detected in the combustion gas, it was suggested that the detected N₂O was generated at a low temperature and decomposed in high-temperature combustion.     

Filippov type plasma focus as intense source of hard X-rays(Ex≃50 keV)

This paper evaluates the use of a plasma focus machine (Filippov type) as a pulsed intense source of hard X-rays. It is shown experimentally that discharging a capacitor bank of W=50 kJ in the new arrangement of the discharge parameters, one can deliver into the test cavity (volume of 6*10³ cm³) an average of Φ _x=8*10^-4 J/cm². The delivered energy fluence varies in the range of 2*10^-4 J/cm²⩽Φ_x⩽2.9*10^-3 J/cm², depending on the probe position. The X-ray energy spectra were established by the differential absorption method using thermo-luminescent detectors (time-integrated spectra) or plastic scintillators (time-resolved spectra). The average energy of X-ray photons is 40 keVx^av<50 keV (20 keV⩽E _x⩽170 keV) and remains quasi-constant during the main part of the pulse (~40 ns). The electron energy that can produce such bremsstrahlung radiation is in the range of 95 keV⩽E_e⩽170 keV. However, time-resolved experiments reveal that at each instant of time only one energy of electron beam occurs. The aforementioned radiation characteristics reveal new potentials for the plasma-focus machine for a variety of applications. Some insight into the physics behind production mechanism of quasi-monoenergetic relativistic-electron beams will be concurrently reviewed