Blar i forfatter "Guio, Patrick"

Viser treff 1-8 av 8

    • Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines. 

      Guio, Patrick; Lilensten, J. (Journal article; Tidsskriftartikkel, 1999)
      In an incoherent scattering radar experiment, the spectral measurement of the so-called up- and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geom- etry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage ...

    • Electron Bulk Heating at Saturn’s Magnetopause 

      Cheng, I; Achilleos, Nicholas; Masters, A; Lewis, G; Kane, M; Guio, Patrick (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-25)
      Magnetic reconnection at the magnetopause (MP) energizes ambient plasma via the release of magnetic energy and produces an “open” magnetosphere allowing solar wind particles to directly enter the system. At Saturn, the nature of MP reconnection remains unclear. The current study examines electron bulk heating at MP crossings, in order to probe the relationship between observed and predicted reconnection ...

    • Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines. 

      Guio, Patrick; Lilensten, J.; Kofman, W.; Bjørnå, Noralv (Journal article; Tidsskriftartikkel, 1998-10-31)
      The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of ...

    • The Impact of Turbulence on the Ionosphere and Magnetosphere 

      Guio, Patrick; Pécseli, Hans L (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-25)
      An important property associated with turbulence in plasmas and fluids is anomalous transport. Plasma, being a good conductor, can in addition be affected by turbulence causing an anomalous resistivity that can significantly exceed its classical counterpart. While turbulent transport may be adequately described in configuration space, some aspects of the anomalous resistivity are best accounted for ...

    • Magnetopause Compressibility at Saturn with Internal Drivers 

      Hardy, Flavien; Achilleos, Nicholas; Guio, Patrick (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-07)
      We use magnetopause crossings of the Cassini spacecraft to study the response of Saturn's magnetosphere to changes in external and internal drivers. We explain how solar wind pressure can be corrected to account for the local variability in internal plasma particle pressure. The physics‐based method is applied to perform the most robust estimation of magnetopause compressibility at Saturn to date, ...

    • Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT 

      Guio, Patrick (Doctoral thesis; Doktorgradsavhandling, 1998-12-18)
      This work presents a study of the electron plasma lines observed by the incoherent scatter radar EISCAT. The work is focusing on two parts. On one hand, the design of a plasma line experiment for the EISCAT system with an improved spatial resolution. On the other hand, the comparison of the plasma line data collected with the EISCAT radar with an improved model for the intensity and the Doppler ...

    • Trapped Particle Motion In Magnetodisc Fields 

      Guio, Patrick; Staniland, Ned; Achilleos, Nicholas; Arridge, Christopher (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-13)
      The spatial and temporal characterization of trapped charged particle trajectories in magnetospheres has been extensively studied in dipole magnetic field structures. Such studies have allowed the calculation of spatial quantities, such as equatorial loss cone size as a function of radial distance, the location of the mirror points along particular field lines (<i>L</i>‐shells) as a function of the ...

    • Weakly nonlinear ion sound waves in gravitational systems 

      Guio, Patrick; Pécseli, Hans L (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-27)
      Ion sound waves are studied in a plasma subject to gravitational field giving rise to vertically inhomogeneous steady-state plasma conditions. Such systems are interesting by exhibiting a wave growth that is a result of energy flux conservation for pulses propagating in an inhomogeneous system. The increase of the amplitude of a pulse as it propagates along the density gradient in the direction of ...