The SPEAR antenna array
THE SPEAR PROJECT HAS NOW FINISHED
SPEAR is a revolutionary new high power radar system which is designed to carry
out research into the Earth's upper atmosphere and magnetosphere, in the
vicinity of the polar cap. This research will help us answer some key
questions about our aerospace environment, particularly the interaction
of the solar wind and the upper atmosphere.
Currently, scientists know that energy and particles which are constantly emitted by the Sun affect the Earth. This energy is primarily deposited over several different altitudes extending from the upper atmosphere to the outer reaches of the Earth’s magnetic field (called the magnetosphere), which encompasses an altitude range of 10’s of km to several thousand km. The energy affects the Earth in many different ways from inducing huge magnetic storms (which produce the aurora) to electrical currents. However, the unpredictability and the type of processes makes it very difficult for scientists to study them in detail.
SPEAR (Space Plasma Exploration by Active Radar) is located on Svalbard above the arctic circle at78.15°N and has been in operation since 2004. The system was designed and built by the Radio and Space Plasma Physics Group at the University of Leicester, UK. UNIS took over ownership of the facility in October 2008.
The facility works by vertically emitting a radio wave (which operates at frequencies of between 4–6 Mhz) where it interacts with the ionosphere (a thin layer of ionised gas or plasma located between ~60km to more than 1000 km in altitude which acts as a boundary between the atmosphere and the magnetosphere). This results in various plasma interaction processes, some of which are outlined above, which are normally caused by the Solar magnetic field and Solar Wind interactions with the geomagnetic field. The ionosphere exhibits different behaviours at different altitudes, so by modifying the frequency and power of the wave scientists can duplicate small scale plasma processes but under more controlled conditions, effectively using the ionosphere as a laboratory. The energy deposited by SPEAR into the ionosphere is <1/10000th of that deposited by the Sun with the effects only last as long as the system is transmitting, so ironically experiments can only be done when the ionosphere is ‘quiet’ (ie. minimal interaction with the Sun).
Longitude 78° 09' 15" N - Latitude 16° 03' 17" E - Altitude 458m (WGS84)
Decimal values: Logitude 78.154° N - Latitude 16.055° E - Altitude 458m (WGS84)