REDNASAJUCI / LECTURER :

Anders Tjulin, Mária Miháliková 

(1) EISCAT Scientific Association, Kiruna, Sweden

NAZOV / TITLE :

EISCAT Scientific Association and EISCAT_3D

ABSTRAKT / ABSTRACT :

The high-latitude atmosphere and ionosphere are important for studies of the relationship between
Solar and Terrestrial conditions as well as for understanding the coupling of the different altitude
regions in the Earth's atmosphere. A large amount of effort has been dedicated to studies in the
polar regions, and more generally the full view of the atmospheric and geospace environment is only
possible through international collaborations. Incoherent scatter (IS) radar systems are important
research tools in the studies of the upper atmosphere and the ionosphere. The standard high-level
data from these systems contain electron density, electron and ion temperatures, and line-of-sight
plasma flow as functions of time and altitude.

There are about a dozen active ISR systems in the world at the present. Three of these systems are
operated in Europe by the EISCAT Scientific Association. These are located in the northernmost
region of the Scandinavian peninsula and on Svalbard.  EISCAT Scientific Association is a non-profit
organisation with headquarters in Kiruna, Sweden. Its aim is to provide access to radar, and other,
high-latitude facilities of the highest technical standard for non-military scientific purposes.

The EISCAT_3D radar system, which is under construction in the European Arctic, will be a
world-leading international research infrastructure using the incoherent scatter technique for
studies of the atmosphere and near-Earth space environment. EISCAT_3D consists of three phased array
antenna sites located in northernmost Norway, Sweden and Finland that, thanks to modern signal
processing and radar techniques, will be able to obtain observations with significantly higher
resolution than is possible with currently operating radar systems. EISCAT_3D will be able to carry
out simultaneous observations within a large volume of the ionosphere above northern Scandinavia,
making it both a good instrument for detailed studies of space weather impacts on the ionosphere as
well as for model verification. The array site at Skibotn, Norway, will have both transmitting and
receiving possibilities and it consists of around 10,000 aerials plus ten 91-aerial outrigger
receivers in the immediate vicinity. The receive-only array sites at Kaiseniemi, Sweden, and
Karesuvanto, Finland, each consist of about 5,000 aerials each. The construction of the system
started after a project kick-off in September 2017. During 2025, EISCAT_3D will gradually begin
operations, starting with a seven-element test system and expanding the operations from that.

EISCAT_3D will replace the EISCAT mainland radars, i.e. the mono-static, 930-MHz UHF radar at Tromsø
and the tri-static, 224-MHz radar at Tromsø with additional receivers at Sodankylä (Finland) and
Kiruna (Sweden). The EISCAT Svalbard Radar (ESR) and the Ionospheric Heating facility at Tromsø will
not be affected by EISCAT_3D becoming operational. Here we will present an overview of the present
status and plans for the EISCAT_3D system.