A bstrocf-Measurements of the visible light obtaining quantitative data difficult. In this paper, we discuss emission from dense, weakly non-ideal Plasmas efforts to measure the average plasma temperature by using have been Performed On the the relative line ratio method. The results using this electrothermal launcher device "SIRENS". The technique are with the results o~conduc~vity, h a plasma is created by the ablation of a Lexan insulator in the source, which then flows through a flux, and mass loss methods for deducing temperature. cylindrical barrel which serves as the material sample. Visible light emission spectra have been observed both in-bore and from the muzzle flash of the barrel, and from the flash of the source.Due to high plasma opacity (the plasma emits as a near blackbody) and absorption by the molecular components of the vapor shield, the hotter core of the arc has been difficult to observe. Recent measurements along the axis of the device indicate time-averaged plasma temperatures in the barrel of about 1 eV for lower energy shots, which agree with experimental measurements of the average heat flux and plasma conductivity along the barrel. Measurements of visible emission from the source indicate time averaged temperatures of 1 to 2 eV which agree with the theoretical estimates derived from ablated mass measurements and calculated estimates derived from plasma conductivity measurements.
The modulation transfer function (MTF) of an amorphous silicon (aSi) sensor array was measured using proper sampling techniques to determine the edge spread function (ESF). The detector under study was a 10 cm2 area detector (EG&G Heimann, RTM128) consisting of 128 x 128 aSi photodiodes arranged in a square array. Two independent methods for calculating the presampling MTF were implemented, based on finely sampling the ESF measurements produced using 40 kV x-rays from a Faxitron microfocal spot x-ray tube. The two calculations of the detector's presampling MTF are in excellent agreement, and are within 20% at the Nyquist frequency when compared with the ideal MTF based only on the size of the detector elements. ESF measurements were also made at 6 MV on a Siemens MD-2 linear accelerator. A calculation of the system presampling MTF was performed which included effects from the linear accelerator source, the lead block used to create the high contrast edge, and the aSi detector response.
The design features and characterization of a new magnetized coaxial plasma source facility for the generation of energetic plasma stream flows are nracsn+arl reraflli Cimnia rlncinn & insA8.inrll I.+Qnm ic.mn avtamgi nnl.mrdelivery system provides high-current ( 2 130 kA) pulses to the plasma source with fast rise ( -2 6 ~s ) . This allows for the production and acceleration of dense ("2 x 10'5cm-3), high-quality (10-40 eV), self-field plasmas to -105 m s-'. We are then afforded the laboratory study of plasma streams with a wide variety of applications including, but not limited to, advanced thrusters for electrlc propulsion, astrophysical jets, critical ionization velocity, magnetic fusion, large-scale plasma etching and depositioli, etc. Comparison to an ideal MHD model is made indicating reasonably good agreement in these self-field discharges, while elucidating the advantages of strong applied magnetization to provide nozzling in a magnetically constricted flow.p"aF'1,'".
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