Blar i forfatter "Gustavsson, Björn Johan"

Viser treff 21-28 av 28

    • Radar observations of thermal plasma oscillations in the ionosphere 

      Vierinen, Juha; Gustavsson, Björn Johan; Hysell, David; Sulzer, M.; Perillat, Phil; Kudeki, Erhan (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-02)
      Incoherent scatter radar observations of ionospheric plasmas rely on echoes from electron density fluctuations with properties governed by the dispersion relations for ion acoustic and Langmuir waves. Radar observations of echoes associated with Langmuir waves (plasma lines) from thermal plasma are weak, and only a few near‐thermal level measurements have been reported. Plasma line echoes are typically ...

    • 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 ...

    • Remote Oxygen Sensing by Ionospheric Excitation (ROSIE) 

      Kalogerakis, K. S.; Gustavsson, Björn Johan; Slanger, T. G.; Rietveld, Michael T; Kendall, E. A.; Pedersen, T. R.; Kosch, M. J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)

    • The science case for the EISCAT_3D radar 

      McCrea, Ian W.; Aikio, Anita; Alfonsi, Lucilla; Belova, Evgenia; Buchert, Stephan C.; Clilverd, Mark; Engler, Norbert; Gustavsson, Björn Johan; Heinselman, C.; Kero, Johan; Kosch, Mike; Lamy, Herve; Leyser, Thomas; Ogawa, Yasunobu; Oksavik, Kjellmar; Pellinen-Wannberg, Asta; Pitout, Frederic; Rapp, Markus; Stanislawska, Iwona; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-29)
      The EISCAT (European Incoherent SCATer) Scientific Association has provided versatile incoherent scatter (IS) radar facilities on the mainland of northern Scandinavia (the EISCAT UHF and VHF radar systems) and on Svalbard (the electronically scanning radar ESR (EISCAT Svalbard Radar) for studies of the high-latitude ionised upper atmosphere (the ionosphere). The mainland radars were constructed ...

    • Science goals for a high-frequency radar and radio imaging array 

      Isham, Brett Cameron; Bullett, Terence; Gustavsson, Björn Johan; Polisensky, Emil; Brum, Christiano; Fallen, Christopher; Belyey, Vasyl; Parra-Rojas, Francisco; Norouzi, Leila; Stramkals, Arturs; Ökten, Mehmet Baran (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-01)
      A medium and high-frequency antenna array for radar and radio imaging of the ionosphere is planned for installation in Aguadilla, Puerto Rico. Science goals include the study of space weather, radio propagation, meteors, lightning, and plasma physics. Radio imaging is ideal for the study of stimulated ionospheric radio emissions, such as those induced by the Arecibo Observatory high-power HF radio ...

    • Simultaneous Global Ionospheric Disturbances Associated With Penetration Electric Fields During Intense and Minor Solar and Geomagnetic Disturbances 

      Zhang, Shun-Rong; Nishimura, Yukitoshi; Vierinen, Juha-Pekka; Lyons, Larry R.; Knipp, Delores J.; Gustavsson, Björn Johan; Waghule, Bhagyashree V.; Erickson, Philip J.; Coster, Anthea J.; Aa, Ercha; Spicher, Andres (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)
      A new observational phenomenon, named Simultaneous Global Ionospheric Density Disturbance (SGD), is identified in GNSS total electron content (TEC) data during periods of three typical geospace disturbances: a Coronal Mass Ejection-driven severe disturbance event, a high-speed stream event, and a minor disturbance day with a maximum Kp of 4. SGDs occur frequently on dayside and dawn sectors, with ...

    • A study of fine structure of diffuse aurora with ALIS-FAST measurements 

      Gustavsson, Björn Johan; Sergienko, T; Sandahl, Ingrid; Andersson, Laila; Brändström, B. U. E.; Steen, Å (Journal article; Tidsskriftartikkel; Peer reviewed, 2008)
      We present results of an investigation of the fine structure of the night sector diffuse auroral zone, observed simultaneously with optical instruments (ALIS) from the ground and the FAST electron spectrometer from space 16 February 1997. Both the optical and particle data show that the diffuse auroral zone consisted of two regions. The equatorward part of the diffuse aurora was occupied by a pattern ...

    • Time-Dependent Electron Transport I: Modelling of Supra-Thermal Electron Bursts Modulated at 5–10 Hz With Implications for Flickering Aurora 

      Gustavsson, Björn Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-04)
      A time-dependent multi-stream electron transport model, AURORA, has been developed for studies of auroral emission-rates during precipitation with large variations on sub-second time-scales. The transport-code accurately takes time-of-flight, energy degradation, scattering and production of secondary electrons into account. AURORA produces ionospheric electron-flux as a function of energy, altitude, ...