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

0358096 - ÚFA 2011 RIV US eng J - Journal Article
Macúšová, Eva - Santolík, Ondřej - Décréau, P. - Demekhov, A. G. - Nunn, D. - Gurnett, D. A. - Pickett, J. S. - Titova, E. E. - Kozelov, B. V. - Rauch, J. L. - Trotignon, J. G.
Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density.
Journal of Geophysical Research. Roč. 115, - (2010), A12257/1-A12257/8. ISSN 0148-0227
R&D Projects: GA ČR GAP205/10/2279; GA MŠMT(CZ) ME10001
Institutional research plan: CEZ:AV0Z30420517
Keywords : Observations * chorus * plasma density * Wideband (WBD) * Cluster
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 3.303, year: 2010

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.
Permanent Link: http://hdl.handle.net/11104/0196217