scholarly journals Methods to determine the radiated power in SPI-mitigated disruptions in JET

2021 ◽  
Vol 92 (2) ◽  
pp. 023502
Author(s):  
J. Lovell ◽  
M. L. Reinke ◽  
U. A. Sheikh ◽  
R. Sweeney ◽  
P. Puglia ◽  
...  
Keyword(s):  
Radiated Power

scholarly journals Dynamic Calibration of GPS Effective Isotropic Radiated Power for GNSS-Reflectometry Earth Remote Sensing

2021 ◽  
pp. 1-12
Author(s):  
Tianlin Wang ◽  
Christopher S. Ruf ◽  
Scott Gleason ◽  
Andrew J. O'Brien ◽  
Darren S. McKague ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Dynamic Calibration ◽  
Earth Remote Sensing ◽  
Radiated Power ◽  
Gnss Reflectometry

Review and present status of the TEXTOR radiative improved (RI) mode

1998 ◽  
Vol 59 (4) ◽  
pp. 587-610 ◽  
Author(s):  
P. E. VANDENPLAS ◽  
A. M. MESSIAEN ◽  
J. P. H. E. ONGENA ◽  
U. SAMM ◽  
B. UNTERBERG
Keyword(s):  
Density Profile ◽  
High Power ◽  
Present Status ◽  
Particle Transport ◽  
Density Limit ◽  
Radiated Power ◽  
Edge Radiation ◽  
Intermediate Size ◽  
Power Fraction ◽  
Better Than

From 1990, the boronized TEXTOR tokamak was characterized by an improved confinement (coined the ‘I mode’) at high power that was substantially better than the L mode, but densities had to be limited to n[bar]e0/nGR[lsim ]0.5–0.6, where nGR is the Greenwald density limit. With the injection of Ne, Si or Ar in order to increase the edge radiation and provided that γ=Prad/Ptot[greater, similar]0.5, PNBI-co/Ptot[greater, similar]0.25 and n[bar]e0/nGR[greater, similar]0.75, a further improved confinement called the radiative improved mode (RI mode) was discovered in 1993 on TEXTOR, a tokamak of intermediate size, and confirmed on TEXTOR-94. The radiated power fraction γ can reach 0.9, and the radiation is nearly isotropically distributed over the torus wall. The RI mode is characterized by its ability to obtain simultaneously and stationarily high densities and high confinement. It is linked to a substantial lowering of edge ne, Te and Ti, a reduction in particle transport and a peaking of the density profile. The RI-mode confinement scales on TEXTOR as τE= (n[bar]e0/nGR)τITERH93-P and values up to n[bar]e0/nGR≈1.2 are obtained. There is no detrimental concentration of the seeded impurity at the centre of the plasma. Results of three different interpretative and modelling approaches are in agreement with the improved confinement features; the preliminary indications are that ITG turbulence is strongly reduced. The Z mode observed on ISX-B has a clear resemblance to the RI mode. The very favourable features of the RI mode justify efforts in trying to establish it on larger machines to verify if the present scaling then holds.

Basic communication sciences

1969 ◽  
Vol 308 (1493) ◽  
pp. 183-198
Keyword(s):  
Long Distance ◽  
Earth Station ◽  
Early Communication ◽  
Technical Developments ◽  
Radiated Power ◽  
The Earth ◽  
Distance Communication ◽  
Quality Of Transmission ◽  
Communication Equipment

The feasibility and utility of long-distance communication via Earth-orbiting satellites has been demonstrated during recent years and it is appropriate therefore to focus attention on the more important scientific studies and technical developments that will be needed if full use is to be made of this valuable mode of communication in the future. The early communication satellites (the Telstar and Relay series) were pioneers in a relatively unknown propagation environment. The satellites themselves were conceptually simple and the communication equipment consisted essentially of a frequency-changing transponder with an r. f. power output of a few watts and a bandwidth some tens of megahertz. Carrier frequencies in the range 2 to 6 GHz were employed; typically either 2 or 6 GHz was used for transmission and 4 GHz for reception at the Earth station. To obtain an adequate signal/noise ratio at the output of the Earth station receiver, frequency modulation was employed, the frequency deviations being greater than those used on terrestrial microwave links. Launcher limitations and other factors meant that the satellites had to be placed in inclined elliptical orbits (see figure 1) with maximum heights of only a few thousand miles. Nevertheless, these satellites demonstrated that some hundreds of frequency-division multiplex telephony circuits, or a television channel, could be achieved with generally satisfactory quality of transmission. It is to be noted, however, that the satellite transponders accommodated only one, or at the most two, r. f. carriers at any time, and that the transmission performance was at times marginal due to limitations of the satellite effective radiated power. Furthermore, these relatively low orbit satellites provided communication in periods of generally less than an hour at a time and required continuous tracking by the Earth station aerials, due to movement of the satellites relative to the Earth.

scholarly journals SATELLITE SEGMENT OF NATIONAL INFORMATION INFRASTRUCTURE. APPROACHES TO IMPLEMENTATION

2020 ◽  
pp. 14-46
Author(s):  
A.M. MELNYK ◽  
Keyword(s):  
Satellite Communications ◽  
Information Infrastructure ◽  
Technology Standards ◽  
Satellite Telecommunication ◽  
National Information Infrastructure ◽  
Telecommunication Systems ◽  
Radiated Power ◽  
Satellite Télécommunication ◽  
National Information ◽  
Communications System

It is proved that the satellite segment is a necessary component of the national information infrastructure. From this position, the state and development trends of satellite telecommunication systems and satellite channel organization technologies are analyzed. It is shown that there are two ways to build a satellite segment: based on the use of leased resources of satellite operators operating in the satellite communications market; based on the resources of the national satellite communications system, which still needs to be created. It is shown that satellite telecommunication systems have a steady tendency to increase the number of spacecraft, until the launch of “heavyˮ satellites with a payload of more than 70 transponders and to increase the frequency resource. The diagram of satellites location density of in orbit is given. In the case of orientation to rent the resources of active spacecraft, the criteria for their selection is indicated. The arc of the geostationary orbit, on which the satellite should be selected, is calculated. For satellites located on this arc, diagrams of equivalent isotropically radiated power values in the C and Ku bands, which they provide in Ukraine, are shown. A list of satellites that you can focus on, recommendations for selection and a list of recommended for the satellite segment is indicated. The technology standards used in payload and methods for organizing satellite communications channels is noticed. To select the parameters of the satellite segment, the results of calculations of the effectiveness of signal-code structures are provided. Approaches to creating a satellite segment of the national information infrastructure are proposed. It is shown that the orientation to the Lybid national satellite does not make sense; a new frequency-orbit resource is required. The types of platforms that can be used on a national satellite are considered.

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