Blar i forfatter "Hosokawa, Keisuke"

Viser treff 1-4 av 4

    • Auroral molecular-emission effects on the atomic oxygen line at 777.4 nm 

      Oyama, Shin-Ichiro; Tsuda, Takuo T.; Hosokawa, Keisuke; Ogawa, Yasunobu; Miyoshi, Yoshizumi; Kurita, Satoshi; Kero, Antti; Fujii, Ryochi; Tanaka, Yoshimasa; Mizuno, Akira; Kawabata, Tetsuya; Gustavsson, Björn Johan; Leyser, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-16)
      One of the representative auroral emission lines that radiates from F-region heights and is measurable on the ground is the 777.4 nm line from excited atomic oxygen. This line has been adopted, along with another E-region emission line, for example 427.8 nm, to estimate the mean energy and total energy flux of precipitating auroral electrons. The influence of emissions from part of the molecular ...

    • An automated auroral detection system using deep learning: real-time operation in Tromsø, Norway 

      Nanjo, Sota; Nozawa, Satonori; Yamamoto, Masaki; Kawabata, Tetsuya; Johnsen, Magnar Gullikstad; Tsuda, Takuo T.; Hosokawa, Keisuke (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-31)
      The activity of citizen scientists who capture images of aurora borealis using digital cameras has recently been contributing to research regarding space physics by professional scientists. Auroral images captured using digital cameras not only fascinate us, but may also provide information about the energy of precipitating auroral electrons from space; this ability makes the use of digital cameras ...

    • 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 ...

    • Reconstruction of precipitating electrons and three-dimensional structure of a pulsating auroral patch from monochromatic auroral images obtained from multiple observation points 

      Fukizawa, Mizuki; Sakanoi, Takeshi; Tanaka, Yoshimasa; Ogawa, Yasunobu; Hosokawa, Keisuke; Gustavsson, Björn Johan; Kauristie, Kirsti; Kozlovsky, Alexander; Raita, Tero; Brändström, Urban; Sergienko, Tima (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-12)
      In recent years, aurora observation networks using high-sensitivity cameras have been developed in the polar regions. These networks allow dimmer auroras, such as pulsating auroras (PsAs), to be observed with a high signal-to-noise ratio. We reconstructed the horizontal distribution of precipitating electrons using computed tomography with monochromatic PsA images obtained from three observation ...