[en] Preliminary studies for Ion Cyclotron Resonance Heating (ICRH) in the frequency range f=3-150 MHz are presented for TJ-IU torsatron. This wide range implies the use of two different theoretical models. The first valid for high frequency, where the WKB approximation is applicable, and the second one which solves the full wave equation in one dimension. The high frequency calculations have been made using a ray tracing code and taking into account the magnetic field and plasma 3-D inhomogeneity. The results obtained in this case are presented in the first paper of this report, being the most important the criterion to avoid Fast Wave (fw)-slow wave (SW) coupling at Lower Hybrid Resonance, near the plasma edge, and the existence of so called Localized Modes. for the low frequency range wave-length is of the size of the plasma radius, therefore, the WKB approximation cannot be used. In this case a 1-D model is used which disregards toroidal effects, to study the main available heating scenarios which are presented in the second work of this report. the studies are made for hydrogen, deuterium and mixed plasmas with and without He³ minority. Finally, the antenna designs to reach these several scenarios are presented in the third paper. Two different antenna models are provided for SW excitation, one of the current type and the other one of potential type. A third antenna is designed to excite FW which is similar to the current type antenna for SW, but rotated 90 degree Celsius

[en] Preliminary studies for ion Cyclotron Resonance Heating (ICRH) in the frequency range f=3-150 MHz are presented for TJ-IU torsatron. This wide range implies the use of two different theoretical models. The first valid for high frequency, where the WKB approximation is applicable, and the second one which solves the full wave equation in one dimension. The high frequency calculations have been made using a ray tracing code and taking into account the magnetic field and plasma 3-D inhomogeneity. The results obtained in this case are presented in the first paper of this report, being the most important the criterion to avoid Fast Wave (FW)-Slow Wave (SW) coupling at Lower Hybrid Resonance, near the plasma edge, and the existence of so called Localized Modes. For the low frequency range wave-length is of the size of the plasma radius, there fore, the WKB approximation cannot be used. In this case a 1-D model is used which disregards toroidal effects, to study the main available heating scenarios which are presented in the second work of this report. The studies are made for hydrogen, deuterium and mixed plasmas with and without He3 majority. Finally, the antenna designs to reach these several scenarios are presented in the third paper. Two different antenna models are provided for SW excitation, one of the current type and the other one of potential type. A third antenna is designed to excite FW which is similar to the current type antenna for SW, but rotated 90 degree centigree. (Author)11 refs

No abstract available

No abstract available

[en] Observations have been made of the supernova remnant 3C 58 with the Westerbork Synthesis Radio Telescope at 6 and 49 cm. These measurements may provide evidence for the possible association of 3C 58 with SN 1181. (Auth.)

[en] A broadband CMOS intermediate frequency (IF) variable-gain amplifier (VGA) for DRM/DAB tuners is presented. The VGA comprises two cascaded stages: one is for noise-canceling and another is for signal-summing. The chip is fabricated in a standard 0.18 μm 1P6M RF CMOS process of SMIC. Measured results show a good linear-in-dB gain characteristic in 28 dB dynamic gain range of -10 to 18 dB. It can operate in the frequency range of 30-700 MHz and consumes 27 mW at 1.8 V supply with the on-chip test buffer. The minimum noise figure is only 3.1 dB at maximum gain and the input-referred 1 dB gain compression point at the minimum gain is -3.9 dBm.

No abstract available

[en] Microstructure crosscorrelation of pulses observed simultaneously at various separations in frequency in the range of 196 to 1420 MHz was done for PSR 0950+08 and PSR 1133+16 at the Arecibo Observatory. Microstructure and subpulse components were identified in the crosscorrelations, and their behaviour vs. pulse longitude was studied. Drastic differences in the subpulse and microspulse behaviour are noted, related in particular to component separation in the double peak average pulse profile of PSR 1133+16. Here the subpulses follow the average pulse profile component separation but the microstructure does not. Interpretation and constraints in terms of some current theories are also presented. (Auth.)

No abstract available

[en] Herringbone Type II bursts were first described by Roberts (1959). These bursts are distinguished by their unusual structure - rib-like features (herringbone) extending on either side of a Type II backbone. The authors report the observed polarization characteristics of 16 events during 1977/1978 (supplemented by results obtained from radio-heliograph observations of six earlier events). (Auth.)