Different types of whistler mode chorus in the equatorial source region. Issue 20 (23rd October 2015)

• Record Type: Journal Article
• Authors: Taubenschuss, Ulrich; Santolík, Ondrej; Graham, Daniel B.; Fu, Huishan; Khotyaintsev, Yuri V.; Le Contel, Olivier
• Is Part Of: Geophysical research letters. Volume 42:Issue 20(2015:Oct.)
• Page Start: 8271
• Page End: 8279
• Publication Date: 2015-10-23
• Subjects: whistler mode -- chorus -- equatorial source -- wave normals -- Gendrin angle -- spectral gap; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL066004
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The Time History of Events and Macroscale Interactions during Substorms‐D spacecraft crossed an active equatorial source region of whistler mode chorus rising tones on 23 October 2008. Rising tones are analyzed in terms of spectral and polarization characteristics, with special emphasis on wave normal angles. The latter exhibit large variations from quasi‐parallel to oblique, even within single bursts, but seem to follow a definite pattern, which enables an unambiguous classification into five different groups. Furthermore, we discuss the frequently observed splitting of chorus bursts into a lower and an upper band around one half of the local electron cyclotron frequency. At chorus frequencies close to the gap, we find significantly lowered wave planarities and a tendency of wave normal angles to approach the Gendrin angle. Key Points: Rare observation of chorus rising tones with/without gap in equatorial source region Systematic variation of chorus wave normal angles (WNA) with frequency Linear/nonlinear wave damping when WNA is close to Gendrin angle