GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Document type
Keywords
Publisher
Language
Years
  • 1
    Electronic Resource
    Electronic Resource
    Theory of azimuthally small-scale hydromagnetic waves in the axisymmetric magnetosphere with finite plasma pressure (1998)
    Springer
    Annales geophysicae 16 (1998), S. 303-321 
    Details
    ISSN: 0992-7689
    Keywords: Magnetosphere ; Azimuthally small-scale waves ; MHD waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The structure of monochromatic MHD-waves with large azimuthal wave number m ≫ 1 in a two-dimensional model of the magnetosphere has been investigated. A joint action of the field line curvature, finite plasma pressure, and transversal equilibrium current leads to the phenomenon that waves, standing along the field lines, are travelling across the magnetic shells. The wave propagation region, the transparency region, is bounded by the poloidal magnetic surface on one side and by the resonance surface on the other. In their meaning these surfaces correspond to the usual and singular turning points in the WKB-approximation, respectively. The wave is excited near the poloidal surface and propagates toward the resonance surface where it is totally absorbed due to the ionospheric dissipation. There are two transparency regions in a finite-beta magnetosphere, one of them corresponds to the Alfvén mode and the other to the slow magneto-sound mode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0303-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    facet.materialart.
    Unknown
    Excitation of drift-compressional mode waves by drift resonance with ring current ions: Arase observation (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-09-18
    Description: Compressional Pc 5 waves are important for the energy dynamics in the terrestrial inner magnetosphere because they can accelerate the relativistic electrons (Ukhorskiy et al., 2009). One of the origins of compressional Pc 5 waves is local plasma instability, but the generation mechanism of the compressional Pc 5 waves is still controversial. Recently, drift compressional instability has been focused on because it can generate compressional waves even if plasma beta is less than unity (Rubtsov et al., 2018; Mager et al., 2019; Takahashi et al., 2022). However, the wave property and excitation mechanism of the drift compressional mode are not fully understood due to the lack of observation. This study reports the role of drift resonance in the excitation of drift compressional waves observed by the Arase satellite on 19th November 2018. From the theoretical calculations of the wave frequency (Mager et al., 2013) and pressure perturbation (Takahashi et al., 2022), we concluded that the observed wave is the drift compressional mode. We estimated the azimuthal wave number (m number) from the finite Larmor radius effect and obtained m ~ -140. This is consistent with the drift resonance with protons at 20-30 keV, whose fluxes showed the most coherent oscillations. In addition to a positive radial gradient of ion temperature, we found that an inward phase space density gradient and positive df/dW sometimes appeared, which indicates that the drift resonance gives free energy to the wave, where f and W are phase space density and energy, respectively.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GFZ OAI
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...