Open AccessObservations of the relationship between frequency sweep rates of chorus wave packets and plasma density
Author(s) -
Macúšová E.,
Santolík O.,
Décréau P.,
Demekhov A. G.,
Nunn D.,
Gurnett D. A.,
Pickett J. S.,
Titova E. E.,
Kozelov B. V.,
Rauch J.L.,
Trotig J.G.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja015468
Subject(s) - chorus , physics , computational physics , narrowband , sweep frequency response analysis , wave packet , plasma , waves in plasmas , atmospheric sciences , atomic physics , acoustics , optics , nuclear physics , art , literature
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.