A state of the art 38.2 MHz Imaging Riometer was installed at Maitri during the austral summer of 2009-2010.
Riometer is a passive instrument that monitors the cosmic radio noise between about 20 and 50 MHz. The field of view of this system at 90 km altitude is 200 x 200 km, a spatial resolution of 20 km with time resolution of 1 sec. The system consists of 16 (4 x 4) crossed dipole antennas and can be upgraded to 64 (8 x 8) system at a later stage. The absorption of the cosmic radio noise is directly related with the ionization density in the 60-90 km altitudes. Energetic particle precipitation in that region directly affects the ionization density. Although Maitri is situated in the sub-auroral latitudes where the magnetic field lines have closed field line configuration and the station is under the influence of global Sq current system. With the increase in magnetic activity, station starts moving under the influence of auroral currents and the field lines become open. The open magnetic field lines offer easy access to the energetic charged particles from space. The system was designed and fabricated in collaboration with Lancaster University, UK, under the project funded by National Centre for Antarctic & Ocean Research (Ministry of Earth Sciences).
Imaging Riometer antenna array at Maitri
Imaging Riometer antenna array at Maitri A typical example of cosmic radio noise absorption and the corresponding magnetic field variations on 05 April 2010 is shown here.