The calculation of the shadow factor of single coil filament
A computer method for calculating the power-reduction factor of a single-coil filament is presented. The filament of incandescent lamps is coiled, which is why a fraction of radiation is trapped in the filament. The relationships between the geometric parameters of a cylindrical helix (pitch ratio and mandrel ratio) and the shadow factor are developed. A FORTRAN program based on the numerical solution of algebraic equations and on three-dimensional numerical integration has been developed.<<ETX>>
Illuminating physics with gas-filled lamps: Exponent-rules
For gas-filled incandescent lamps we exploit the fact that their operation is significantly affected by coiling of the filament, convective-conductive loss in the Langmuir sheath and backscattering of tungsten atoms by the gas. These features are incorporated as correction factors in the temperature indices which parameterize the intrinsic properties of tungsten such as emissivity, resistivity, evaporation rate, etc together with the bulb observables e.g., life, lumen, power, etc. A chi squares procedure is adopted to the said index corrections leading to excellent reproduction of 14 exponent-rules. The resulting temperature parameterizations can be profitably employed in any application related to gas-filled lamps.
Simulation study of high power microwave generation by virtual cathode oscillation in coaxial vircator
Summary form only given, as follows. We have numerically simulated the high power microwave generation by virtual cathode oscillation in a coaxial vircator with 3 dimensional PIC code Magic. It is noted that the coaxial vircator has the advantage of an enhancement of power efficiency and gaining of narrow bandwidth frequency. The study is focused on the design of a diode structure for a coaxial vircator suitable for Chundoong IREB pulser (Max. 600 kV, 85 kA, 60 ns). It consists of a center annular cathode, a cylindrical meshed-anode and a reflector. The simulation results showed that the coaxial vircator can indeed be operated at the selected frequency with the narrow bandwidth and the microwave output power strongly depends on the position and geometry of the reflector. From this simulation results we expect that the maximum microwave output power will be obtained by the reflector of 4 cm in width and also 4 cm in distance away from the IREB, where the resonant frequency of microwave from coaxial vircator is simulated to be 6.577 GHz.