Global Model of Whistler Mode Chorus in the Near‐Equatorial Region (|<i>λ</i><sub><i>m</i></sub>|< 18°)
Nigel P. Meredith, R. B. Horne, Xiaochen Shen, Wen Li, Jacob Bortnik
Abstract
Abstract We extend our database of whistler mode chorus, based on data from seven satellites, by including ∼3 years of data from Radiation Belt Storm Probes (RBSP)‐A and RBSP‐B and an additional ∼6 years of data from Time History of Events and Macroscale Interactions during Substorms (THEMIS)‐A, THEMIS‐D, and THEMIS‐E. The new database allows us to probe the near‐equatorial region in detail, revealing new features. In the equatorial source region, | λ m |<6°, strong wave power is most extensive in the 0.1–0.4 f c e bands in the region 21–11 magnetic local time (MLT) from the plasmapause out to L ∗ = 8 and beyond, especially near dawn. At higher frequencies, in the 0.4–0.6 f c e frequency bands, strong wave power is more tightly confined, typically being restricted to the postmidnight sector in the region 4< L ∗ <6. The global distribution of strong chorus wave power changes dramatically with increasing magnetic latitude, with strong chorus waves in the region 12<| λ m |<18° predominantly observed at frequencies below 0.3 f c e in the prenoon sector, in the region 5< L ∗ <8.