TITLE:
Determination of Instantaneous Frequencies of Low Plasma Waves in the Magnetosheath Using Empirical Mode Decomposition (EMD) and Hilbert Transform (HT)
AUTHORS:
Ekong Ufot Nathaniel, Nyakno Jimmy George, Sunday Edet Etuk
KEYWORDS:
Plasma Waves; Instantaneous Frequency; Empirical Mode Decomposition (EMD); Hilbert Transform (HT)
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.3 No.4,
October
15,
2013
ABSTRACT:
The observations of in-situ spacecraft mission in the
magnetosheath and a region of
thermalized subsonic plasma behind the bow shock reveal a non-linear behaviour
of plasma waves. The study of waves and optics in Physics has given the
understanding of the effect of many waves coming together to form a wave field
or wave packet. The common aspect of such study shows that two or more waves
can superimpose constructively or destructively. The sudden high magnetic field
data in the magnetosheath displays such possibility of superposition of waves.
In this paper, we use the empirical mode decomposition (EMD) and Hilbert
transform (HT) techniques to determine the instantaneous frequencies of low
frequency plasma waves in the magnetosheath. Our analysis has shown that the turbulent
behavior of magnetic field in the magnetosheath within the selected period is
due to superposition of waves.