Coherent Back-Scatter Radar 50 MHz (RESCO)

The Coherent Back-Scatter Radar of 50 MHz (RESCO) was installed at the Space Observatory of São Luís / INPE, whose operation begun in August of 1998, is capable to accomplish measures of dynamics of the plasma of the electrojet and of bubbles equatorial ionospheric. This radar was projected to map the turbulence and the electromagnetic drift of the irregularities of short length scale (3 meters) in a height range that extends from ~90 km to ~1000 km of the equatorial ionosphere. Such plasma irregularities have big influence in the propagation trans-ionosphere of waves in a great frequency range, VHF to UHF, and, therefore, it influence all of the activities of space communications of the Brazilian tropical area. The formation, the development and the space distribution of these irregularities are highly sensitive to the space climatic change (in other words, "Space Weather") besides the convection processes and of the storms of the troposphere.

This radar resulted of the development and construction begun in INPE there are several years. It transmits signs pulse of high potency through an network antenna with 768 dipoles which allow to concentrate all the energy transmitted in only narrow beam radiation. The same antenna also captures the echo signs spread by the irregularities ionosphere. The transmitted maximum power (120 kW) it is reached through the use of a modular system of 8 transmitters in phase to maximize the transmitted energy. The operational control of the radar is made by a computer, which also accomplishes the acquisition, the treatment and processing 'on line' of the received data of the ionosphere. The data recorded are available also for the processing and analyze subsequent. This radar was already operated in several campaigns since 1998 and now it is collecting in a routine way data of the dynamics of the equatorial electrojet.

This radar, with the FCI radar of 30 MHz together offers great opportunities to the researchers of studying the peculiar phenomenon of the equatorial area. These, beside the radars of Peru (Jicamarca), of the India (Thumba) and of the Indonesia, are some of the few radars of this type that exist in the world around of the magnetic equator. Due to the peculiar configuration of the geomagnetic field, the Brazilian equatorial area have characteristics very different from the other areas. It was for this reason that NASA of the USA, in collaboration of INPE, accomplished in Alcântara in 1994 the campaign GUARÁ when 26 rockets were thrown (in the period of September-October) to study the equatorial electrojet and the bubbles ionosphere. In this campaign were used another radar similar to the radar RESCO (which was brought of the USA), Digissonde (which provided the diagnoses of the ionosphere) and of the magnetometers operated by INPE in the Space Observatory of São Luís. The radar RESCO, that is now in a phase of technological improvement, offers great potential to promote researches of the environment of the Brazilian equatorial area. 

Rua Horto Florestal, 100, Cruzeiro Santa Bárbara, Sao Luis-MA - Brasil 

SOURCE: São Luiz Space Observatory