Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density

E Macúšová (1, 2) , O Santolík (2, 1) , Pierrette Décréau (3) , A. G. Demekhov (4) , D Nunn (5) , D.A. Gurnett (6) , J.S. Pickett (7) , E. E. Titova (8) , B. V. Kozelov (9, 8) , Jean-Louis Rauch (3) , Jean-Gabriel Trotignon (3)

1 IAP - Institute of Atmospheric Physics [Prague]
2 Faculty of Mathematics and Physics [Praha/Prague]
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
4 Institute of Applied Physics of RAS
5 ECS Department - University of Southampton
6 Department of Physics and Astronomy [Iowa City]
7 Department of Physics and Astronomy [Ames, Iowa]
8 PGI - Polar Geophysical Institute of Russian Academy of Sciences
9 IKI - Space Research Institute of the Russian Academy of Sciences

[1] Chorus emissions are generated by a nonlinear mechanism involving wave‐particle interactions with energetic electrons. Discrete chorus wave packets are narrowband tones usually rising (sometimes falling) in frequency. We investigate frequency sweep rates of chorus wave packets measured by the Wideband data (WBD) instrument onboard the Cluster spacecraft. In particular, we study the relationship between the sweep rates and the plasma density measured by the WHISPER active sounder. We have observed increasing values of the sweep rate for decreasing plasma densities. We have compared our results with results of simulations of triggered emissions as well as with estimates based on the backward wave oscillator model for chorus emissions. We demonstrate a reasonable agreement of our experimental results with theoretical ones. Citation: Macúšová, E., et al. (2010), Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density,

Domaines: Planète et Univers [physics]

E Macúšová, O Santolík, Pierrette Décréau, A. G. Demekhov, D Nunn, et al.. Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density. Journal of Geophysical Research Space Physics, 2010, 115, A12257 (8 p.). ⟨10.1029/2010JA015468⟩. ⟨insu-01180755⟩