IDEAS home Printed from https://ideas.repec.org/a/nat/natcom/v6y2015i1d10.1038_ncomms8703.html
   My bibliography  Save this article

Observations of discrete harmonics emerging from equatorial noise

Author

Listed:
  • Michael A. Balikhin

    (University of Sheffield)

  • Yuri Y. Shprits

    (UCLA
    MIT)

  • Simon N. Walker

    (University of Sheffield)

  • Lunjin Chen

    (W.B. Hanson Center for Space Sciences, The University of Texas at Dallas)

  • Nicole Cornilleau-Wehrlin

    (LPP, CNRS, École Polytechnique
    LESIA, Observatoire de Paris, Section de Meudon)

  • Iannis Dandouras

    (CNRS, IRAP
    UPS-OMP, IRAP)

  • Ondrej Santolik

    (Institute of Atmospheric Physics ASCR
    Faculty of Mathematics and Physics, Charles University in Prague)

  • Christopher Carr

    (Blackett Laboratory, Imperial College London, South Kensington Campus)

  • Keith H. Yearby

    (University of Sheffield)

  • Benjamin Weiss

    (MIT)

Abstract

A number of modes of oscillations of particles and fields can exist in space plasmas. Since the early 1970s, space missions have observed noise-like plasma waves near the geomagnetic equator known as ‘equatorial noise’. Several theories were suggested, but clear observational evidence supported by realistic modelling has not been provided. Here we report on observations by the Cluster mission that clearly show the highly structured and periodic pattern of these waves. Very narrow-banded emissions at frequencies corresponding to exact multiples of the proton gyrofrequency (frequency of gyration around the field line) from the 17th up to the 30th harmonic are observed, indicating that these waves are generated by the proton distributions. Simultaneously with these coherent periodic structures in waves, the Cluster spacecraft observes ‘ring’ distributions of protons in velocity space that provide the free energy for the waves. Calculated wave growth based on ion distributions shows a very similar pattern to the observations.

Suggested Citation

  • Michael A. Balikhin & Yuri Y. Shprits & Simon N. Walker & Lunjin Chen & Nicole Cornilleau-Wehrlin & Iannis Dandouras & Ondrej Santolik & Christopher Carr & Keith H. Yearby & Benjamin Weiss, 2015. "Observations of discrete harmonics emerging from equatorial noise," Nature Communications, Nature, vol. 6(1), pages 1-6, November.
    • Handle: RePEc:nat:natcom:v:6:y:2015:i:1:d:10.1038_ncomms8703
    DOI: 10.1038/ncomms8703
    as

    Download full text from publisher

    File URL: https://www.nature.com/articles/ncomms8703
    File Function: Abstract
    Download Restriction: no
    File URL: https://libkey.io/10.1038/ncomms8703?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    More about this item

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:nat:natcom:v:6:y:2015:i:1:d:10.1038_ncomms8703. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Sonal Shukla or Springer Nature Abstracting and Indexing (email available below). General contact details of provider: http://www.nature.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.