• Seasonal and solar cycle variations of thermally excited 630.0 nm emissions in the polar ionosphere 

      Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad; Laundal, Karl Magnus (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used to derive the thermal emission intensity. Thermally excited emissions have been found to maximize at solar maximum with peak occurrence rate of ∼40% compared to ∼2% at solar minimum. ...
    • A new five-wavelength photometer operated in Tromsø (69.6°N, 19.2°E) 

      Nozawa, Satonori; Kawabata, Tetsuya; Hosokawa, Keisuke; Ogawa, Yasunobu; Tsuda, Takuo; Mizuno, Akira; Fujii, Ryoichi; Hall, Chris (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-11)
      A new fve-wavelength photometer was developed and installed at the EISCAT Tromsø site (69.6°N, 19.2°E) in January 2017. The photometer consists of two units: an optical unit and a control unit together with a PC. The photometer is capable of simultaneously observing auroral emissions with fve wavelengths. A uniqueness of the present system is its capability of precise pointing, which enables ...