EISCAT

EISCAT Sodankylä receiver antenna (diameter 32m) after conversion to 224 MHz (crossed dipole replaced Cassegrain subreflector at focal point)

EISCAT Kiruna Radar (diameter 32m)

EISCAT(European Incoherent Scatter Scientific Association) operates threeincoherent scatterradarsystems in NorthernScandinaviaandSvalbard.The facilities are used to study the interaction between theSunand theEarthas revealed by disturbances in theionosphereandmagnetosphere.

The EISCAT Scientific Association exists to provide scientists with access to incoherent scatter radar facilities of the highest technical standard.

EISCAT 3D

The construction of EISCAT's new generation of incoherent radars: EISCAT 3D, has started in November 2022.

The first stage of the new system will consist of three radar sites, functioning together, just as the old mainland system. Later, transmitter up grade and more sites will be added to the system.

Instead of parabolic dishes, as the old system, EISCAT 3D is amultistatic radarcomposed of threephased-arrayantenna fields. Many small antennas working together as one. Each field will have between 5 000 - 10 000 crosseddipole antennamounted on top of a ground plane 70 meters in diameter.

The core site of EISCAT 3D is located just outsideSkibotn,Norway. The facility will have 109 hexagonal antenna units as its main antenna, and 10 antenna units spread out around the main site. On top of the antenna units the dipole antennas are mounted. The Skibotn facility will have 10 000 of these small antennas. The Skibotn facility will act both as a transceiver and receiver of the EISCAT 3D system.

Two receiver sites are located inKaresuvando,Finland and Kaiseniemi, Sweden. The facilities will consist of 54 and 55 antenna units with approximately 5 000 dipole antennas.

Space debristracking, tracking ofmeteorites,research onGPSand radio traffic,space weather,auroraresearch,climateresearch and near-Earth space are some of the areas where EISCAT 3D will be able to offer much more flexible and meticulous research data.

The use of EISCAT 3D is solely civil.

The two antennas of the EISCAT Svalbard Radar

The new system should be up and running 2023/2024. This also means that the old mainland system will be dismantled.

The mainland system

The mainland system consisted of three parabolic dish research radar antennas, designed as a tristatic radar, that is, three facilities that work together. The radar antennas are located inTromsø,Norway;Sodankylä,Finland andKiruna,Sweden, north of theScandinavianArctic Circle.

The core in the tri-static system, is located at Ramfjordmoen, outside Tromsø, Norway with a 32 meter mechanically fully steerable parabolic dish used for transmission and reception in theUHF-band. Operating in the 930 MHz band with a transmitter peak power 2.0 MW, 12.5% duty cycle and 1 μs – 10 ms pulse length with frequency and phase modulation capability.

And theVHFradar that operates in the 224 MHz band with transmitter peak power 3 MW, 12.5% duty cycle and 1 μs – 2 ms pulse length with frequency and phase modulation capability. The antenna, used for transmission and reception, is a parabolic cylinder antenna consisting of 4 quarters, constituting a total aperture of 120 m x 40 m. This antenna is mechanically steerable in the meridional plane (-30° to 60° zenith angle), and electronically steerable in the longitudinal direction (±12° off-boresight).

EISCAT Ramfjordmoen facility (near Tromsø) in winter

The receiving antennas in Sodankylä, Finland and Kiruna, Sweden, is fully steerable 32 meter parabolic dish antennas. The receivers include multiple channels the UHF radar and the VHF radars. The data are pre-processed in signal processors, displayed and analysed in real-time and can be recorded to mass storage media.

EISCAT Svalbard Radar

The location inLongyearbyen,Svalbard,high above the arctic circle and near the north pole, offers unique capabilities in auroral research. Svalbard’s unique climate with polar night from November until February, make the season for observing the northern lights long.

The EISCAT Svalbard Radar (ESR) also operates the UHF-band, at 500 MHz with a transmitter peak power of 1000 kW, 25 % duty cycle and 1 μs – 2 ms pulse length with frequency and phase modulation capability.There are two antennas, a 32 meter mechanically fully steerable parabolic dish antenna, and a 42 meter fixed parabolic antenna aligned along the direction of the local geomagnetic field.

The whole radar system is controlled by computers, and the sites in Tromsø, Kiruna, Sodankylä, and Longyearbyen are interconnected via the Internet.

Tromsø Ionospheric Modification facility

Anionospheric heatingfacility, Heating, is also located in Ramfjordmoen outside Tromsø, Norway. It consists of 12 transmitters of 100 kW CW power, which can be modulated, and three antenna arrays covering the frequency range 3.85 MHz to 8 MHz.

History

EISCAT was founded in December 1975, as an association of research councils in six member countries. But the plans to establish a research facility focusing on incoherent scatter technology in the Northern Lights zone, started as early as 1969. Many meetings with interested researchers were held in the early 70s, but it was not untilProfessor Sir Granville Beynonorganized a meeting in 1973, where a board and a chairman were appointed, that the work really began. In 1974, the Council presented a report on how the organisation, operations and implementation of EISCAT's UHF system could take place, and at the end of 1975 the first six member states agreed to start the work towards the construction of EISCAT.

The member countries are now Sweden, Norway, Finland, Japan, China and the United Kingdom. The members have changed somewhat: Germany is no longer a full member, France was a member from the start of the organization in 1975 until 2005, while Japan and China were added later (1996 and 2007 respectively).

EISCAT is governed byThe EISCAT Council,which consists of representatives from research institutions in the various member countries. Two committees, the Administrative and Financial Committee (AFC) and the Advisory Scientific Committee (SAC), assist the Council in its work.

External links

• https://eiscat.se/about/
• https://eiscat.se/eiscat3d-information/
• https://eiscat.se/eiscat3d-information/eiscat_3d-faq/
• University Courses on Svalbard (UNIS)