• 20 years of research on the Alcator C-Mod tokamak 

      Greenwald, Martin; Bader, A; Baek, S; Bakhtiari, M; Barnard, H; Beck, W; Bergerson, W; Bespamyatnov, I; Bonoli, P; Brower, D; Brunner, D; Burke, W; Candy, J; Churchill, M; Cziegler, I; Diallo, A; Dominguez, A; Duval, B; Edlund, E; Ennever, P; Ernst, D; Faust, I; Fiore, C; Fredian, T; Garcia, Odd Erik; Gao, C; Goetz, J; Golfinopoulos, T; Granetz, R; Grulke, O; Hartwig, Z; Horne, S; Howard, N; Hubbard, A; Hughes, J; Hutchinson, I; Irby, J; Izzo, V; Kessel, C; Labombard, B; Lau, C; Li, C; Lin, Y; Lipschultz, B; Loarte, A; Marmar, E; Mazurenko, A; McCracken, G; McDermott, R; Meneghini, O; Mikkelsen, D; Mossessian, D; Mumgaard, R; Myra, J; Nelson-Melby, E; Ochoukov, R; Olynyk, G; Parker, R; Pitcher, S; Podpaly, Y; Porkolab, M; Reinke, M; Rice, J; Rowan, W; Schmidt, A; Scott, S; Shiraiwa, S; Sierchio, J; Smick, N; Snipes, JA; Snyder, P; Sorbom, B; Stillerman, J; Sung, C; Takase, Y; Tang, V; Terry, J; Terry, D; Theiler, C; Tronchin-James, A; Tsujii, N; Vieira, R; Walk, J; Wallace, G; White, A; Whyte, D; Wilson, J; Wolfe, S; Wright, G; Wright, J; Wukitch, S; Zweben, S (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • An Advanced Non-Gaussian Feature Space Method for POL-SAR Image Segmentation 

      Doulgeris, Anthony Paul; Eltoft, Torbjørn (Conference object; Konferansebidrag, 2013)
      This work extends upon our simple feature-based multichannel SAR segmentation method to incorporate highly desirable statistical properties into a computationally simple approach. The desirable properties include Markov ...
    • Amplitude and size scaling for interchange motions of plasma filaments 

      Kube, Ralph; Wiesenberger, Matthias; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-07)
      The interchange dynamics and velocity scaling of blob-like plasma filaments are investigated using a two-field reduced fluid model. For incompressible flows due to buoyancy, the maximum velocity is proportional to the ...
    • Auroral ion acoustic wave enhancement observed with a radar interferometer system 

      Schlatter, Nicola M.; Belyey, Vasyl; Gustavsson, Björn Johan; Ivchenko, Nickolay; Whiter, Daniel; Dahlgren, Hanna; Tuttle, Sam; Grydeland, Tom (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-20)
      Measurements of naturally enhanced ion acoustic line (NEIAL) echoes obtained with a five-antenna interferometric imaging radar system are presented. The observations were conducted with the European Incoherent SCATter ...
    • The auroral red line polarisation: modelling and measurements 

      Lilensten, J.; Bommier, V.; Barthelemy, M; Lamy, Herve; Bernard, D; Moen, Jøran Idar; Johnsen, Magnar Gullikstad; Løvhaug, Unni Pia; Pitout, Frederic (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-12)
      In this work, we model the polarisation of the auroral red line using the electron impact theory developed by Bommier et al. (2011). This theory enables the computation of the distribution of the Degree of Linear Polarisation ...
    • Auto-correlation function and frequency spectrum due to a super-position of uncorrelated exponential pulses 

      Garcia, Odd Erik; Theodorsen, Audun (Peer reviewed, 2017-03)
      The auto-correlation function and the frequency power spectral density due to a super-position of uncorrelated exponential pulses are considered. These are shown to be independent of the degree of pulse overlap and thereby ...
    • An Automatic U-distribution and Markov Random Field Segmentation Algorithm for PolSAR Images 

      Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
    • The behavior of electron density and temperature during ionospheric heating near the fifth electron gyrofrequency 

      Wu, Jun; Wu, Jian; Rietveld, Michael T.; Häggström, I.; Zhao, Haisheng; Xu, Zhengwen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-27)
      The experimental phenomena involving the changes in electron temperature and electron density as a function of pump frequency during an ionospheric heating campaign at European Incoherent Scatter near Tromsø, Norway, are ...
    • Blob Sizes and Velocities in the Alcator C-Mod Scrape-Off Layer 

      Kube, Ralph; Garcia, Odd Erik; LaBombard, Brian; Madsen, Jens; Terry, James L.; Zweben, Stewart (Conference object; Konferansebidrag, 2012)
      A new blob-tracking algorithm for the GPI diagnostic installed in the outboard-midplane of Alcator C-Mod is developed. I t tracks large-amplitude fluctuations propagating through the scrape-off layer and calculates blob ...
    • Blob sizes and velocities in the Alcator C-Mod scrape-off layer 

      Kube, Ralph; Garcia, Odd Erik; LaBombard, Brian; Terry, J.L; Zweben, Stewart (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Gas-puff imaging data is used to investigate the dynamics of blob-like structures in the scrape-off layer of Alcator C-Mod. A blob-tracking algorithm is developed and used to compute blob propagation velocities and cross-field ...
    • Burst statistics of fluctuations in a simple magnetized torus configuration 

      Rypdal, Kristoffer; Živkovic, Tatjana; Østvand, Lene (Working paper; Arbeidsnotat, 2009-04-19)
      In a toroidal plasma confined by a purely toroidal magnetic field the plasma transport is governed by electrostatic turbulence driven by the flute interchange instability on the low-field side of the torus cross section. ...
    • Capillary suction model as pipes of different sizes: flow conditions and comparison with experiments 

      Nguyen, Hung Thanh; Jacobsen, Stefan; Melandsø, Frank (Conference object; Konferansebidrag, 2012)
      ABSTRACT Absorption of water in concrete is often described by the simple linear water uptake vs. square-root-of-time law. However, a deviation from this behaviour is frequently seen depending on factors such as initial ...
    • A case study on generation mechanisms of a sporadic sodium layer above Tromsø (69.6° N) during a night of high auroral activity 

      Takahashi, Toru; Nozawa, Satonaori; Tsuda, Takuo T.; Ogawa, Yasunobu; Saito, Norihito; Hidemori, Takehiro; Kawahara, Takuya D.; Hall, Chris; Fujiwara, Hitoshi; Matuura, Nobuo; Brekke, Asgeir; Tsutsumi, Masaki; Wada, Satoshi; Kawabata, Tetsuya; Oyama, Shinichiro; Fujii, Ryoichi (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-05)
      We have quantitatively evaluated generation mechanisms of a sporadic sodium layer (SSL) based on observational data obtained by multiple instruments at a high-latitude station: Ramfjordmoen, Tromsø, Norway (69.6° N, 19.2° ...
    • Characterization and discrimination of evolving mineral and plant oil slicks based on L-band synthetic aperture radar (SAR) 

      Jones, Cathleen; Espeseth, Martine Mostervik; Holt, Benjamin; Brekke, Camilla; Skrunes, Stine (Peer reviewed, 2016-10-18)
      Evolution of the damping ratio for Bragg wavenumbers in the range 32-43 rad/m is evaluated for oil slicks of different composition released in the open ocean and allowed to develop naturally. The study uses quad-polarimetric ...
    • Characterization of a waveguide Mach-Zehnder interferometer using PDMS as a cover layer 

      Lindecrantz, Susan Mariah; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      A Mach-Zehnder interferometer made with shallow rib waveguides is studied experimentally and using simulations. The rib-height giving single-mode guidance is found as function of core thickness and polarization. Devices ...
    • Chip-based optical microscopy for imaging membrane sieve plates of liver scavenger cells 

      Helle, Øystein Ivar; Øie, Cristina Ionica; McCourt, Peter Anthony; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-26)
      The evanescent field on top of optical waveguides is used to image membrane network and sieve-plates of liver endothelial cells. In waveguide excitation, the evanescent field is dominant only near the surface (~100-150 ...
    • Climatic trends in E-region critical frequency and virtual height above Tromsø (70 degrees N, 10 degrees E) 

      Cannon, P. S.; Hall, Chris; Brekke, Asgeir (Journal article; Tidsskriftartikkel; Peer reviewed, 2007-11-29)
      We have examined the long time series of observations of E-region virtual height (1948–2006) and critical frequency (1935-2006) hitherto made by the Tromsø ionosonde at 70 degrees N, 19 degrees E. Combining a simplistic ...
    • Comparison of feature based segmentation of full polarimetric SAR satellite sea ice images with manually drawn ice charts 

      Moen, Mari-Ann; Doulgeris, Anthony Paul; Anfinsen, Stian Normann; Renner, Angelika H.H.; Hughes, Nick; Gerland, Sebastian; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this paper we investigate the performance of an algorithm for automatic segmentation of full polarimetric, synthetic aperture radar (SAR) sea ice scenes. The algorithm uses statistical and polarimetric properties of ...
    • A comparison of overshoot modelling with observations of polar mesospheric summer echoes at radar frequencies of 56 and 224 MHz 

      Havnes, Ove; Pinedo Nava, Henry; La Hoz, Cesar; Senior, Andrew; Hartquist, Thomas W.; Rietveld, Michael T; Kosch, Michael J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      We have compared radar observations of polar mesospheric summer echoes (PMSEs) modulated by artificial electron heating, at frequencies of 224 MHz (EISCAT VHF) and 56 MHz (MORRO). We have concentrated on 1 day of observation, ...
    • Comparison of the orientation of small-scale electron density irregularities and F region plasma flow direction. 

      Tereshchenko, E.D.; Rietveld, Michael T.; Brekke, Asgeir; Khudukon, B.Z.; Kozlova, M.O.; Evstafiev, O.V.; Nygren, T. (Journal article; Peer reviewed; Tidsskriftartikkel, 2000)
      Results are shown from an experimental campaign where satellite scintillation was observed at three sites at high latitudes and, simultaneously, the F region plasma flow was measured by the nearby EISCAT incoherent scatter ...