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A computational study is reported of the effect of small changes in the direction, polarization, and divergence of the incident laser beam on the reflectance of a transparent plate. The calculations were made to determine the most... more
A computational study is reported of the effect of small changes in the direction, polarization, and divergence of the incident laser beam on the reflectance of a transparent plate. The calculations were made to determine the most suitable beam splitter geometry for monitoring a linearly polarized laser beam. A description is given of an instrument, based on these design considerations, which is insensitive to the investigated changes in beam geometry.
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Tormac (Toroidal Magnetic Cusp) is a plasma confinement concept combining the favorable magnetohydrodynamic stability properties of a cusp geometry with the good particle confinement inherent to closed field geometry. A conceptual Tormac... more
Tormac (Toroidal Magnetic Cusp) is a plasma confinement concept combining the favorable magnetohydrodynamic stability properties of a cusp geometry with the good particle confinement inherent to closed field geometry. A conceptual Tormac plasma has two regions; an interior region in which a toroidal bias or stuffing field is embedded, and an exterior or surface region confined by mirror trapping along open field lines. The combination of these two regions is expected to lead to a configuration having confinement substantially superior to that of a mirror, and to allow the plasma to be stable to high β. The Tormac V experiment is an attempt to establish such a configuration and to investigate the characteristic behavior of the Tormac plasma. The Tormac concept, the Tormac V experimental setup, and the results are described.
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ABSTRACT
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An experimental study of the structure of a normal ionizing shock in helium suggests that the shock is essentially resistive with the major dissipative mechnism being ohmic heating of ions and neutrals by ion currents.
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A kernel is developed that enables a bandlimited signal to be optimally reconstructed from a finite number N of samples taken at the Nyquist rate or faster. The point reconstruction error, which falls as only N−0.5 at the Nyquist... more
A kernel is developed that enables a bandlimited signal to be optimally reconstructed from a finite number N of samples taken at the Nyquist rate or faster. The point reconstruction error, which falls as only N−0.5 at the Nyquist frequency, drops exponentially with N if there is even moderate oversampling.
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A start-up method for producing a plasma in the bi-cusp field configuration of a toroidal magnetic cusp (TORMAC) is described. The method uses the radial injection and trapping of a toroidal gun plasma. Measurements of an injected plasma... more
A start-up method for producing a plasma in the bi-cusp field configuration of a toroidal magnetic cusp (TORMAC) is described. The method uses the radial injection and trapping of a toroidal gun plasma. Measurements of an injected plasma with a velocity of 17 μsec–1 and 4·5 × 1018 particles is presented. The plasma was observed to be stopped and trapped in an equilibrium position. A well-defined outer boundary remained stationary for 20 μsec. Particle flux distribution emanating from the cusp field lines defined a sheath having a width of 1–1·5 ion gyroradii in the poloidial field. This translates to a narrow outer boundary and a broad inner boundary based on the gradient of the poloidial field at the two radial positions. Measurements of Thomson scattering and interferometry give a Te of 15eV, a 15μsec density decay time, and a 5μsec energy decay time. These results show that this injection and trapping method is successful, and thus a higher gun plasma energy combined with a flux ...