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The
Andoya
Imaging Riometer for
Ionospheric Studies -
AIRIS
Last update: Sept. 13th.
2006
AIRIS Beam
Projection
Array heading: 0 deg. north
AIRIS Location on Andoya, Norway
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The
ALOMAR Observatory (And?a Rocket Range) has in 2002 started the
process of building an imaging riometer at And?a in cooperation
with the (Riometer) Lancaster
University in England, UK and (Array) Genesis
Software Pty Ltd in Australia.
The system has,
except for a newer technology in most areas the
same basic features as the existing Imaging Riometer for
Ionospheric Studies (IRIS) system installed in Northern Finland,
installed by the Lancaster Ionosphere and Radio Propagation
Group.
The new AIRIS system has a sophisticated
phased array antenna which produces 49 narrow beams, of the order
of 12 degrees beam width. The riometer outputs are all sampled
once per second. The AIRIS system is capable of examining
ionospheric electron density perturbations in both small time scale (1
second), as well as small spatial scale (approx. 20 km). This
enables the structure and dynamics of the energetic particle
precipitation over a large field of view to be determined with a
spatial resolution, which is not at presently obtainable with any
other technique.
Preliminary data from the new Imaging riometer is available on-line at all time.
The research topics employing the AIRIS system include:
Ionospheric
scintillation and its effect upon satellite communication.
Auroral
absorption and its effect upon HF wave propagation
Dynamics
and structure of energetic particle precipitation
Artificially
induced absorption and scintillation
Gloria
The
AIRIS is a part of the Global Riometer Array (Gloria) which
is an international collaborative program for scientific
investigation of the role of particle precipitation in the
sun-earth connection. In partucular it aims at an improved understanding of the coupling
mechanism between the solar wind, magnetsophere and the
ionosphere. There are currently over 20 imaging riometer arrays
worldwide.
AIRIS Technical data:
-
38.2 MHz, BW: 250 kHz, Sens: 0.05 dB
- 64 (8x8) crossed
dipoles, filled
array
- 49 narrow beams, 12 degrees BW
- Spatial
resolution: 20 km
- Sampling rate: 1 second.
- Digital Rx
and beam shaping FPGA
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Fixed circular polarization
- 45 deg. antenna angle to
minimize mutual coupling.
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