Electromagnetic disturbances observed near the dip region ahead of dipolarization front. Issue 7 (6th April 2016)

• Record Type: Journal Article
• Authors: Zhao, D.; Fu, S. Y.; Sun, W. J.; Parks, G. K.; Zong, Q. G.; Shi, Q. Q.; Pu, Z. Y.; Cui, Y. B.; Wu, T.; Liu, J.; Zhou, X. Z.
• Is Part Of: Geophysical research letters. Volume 43:Issue 7(2016)
• Page Start: 3026
• Page End: 3034
• Publication Date: 2016-04-06
• Subjects: Dipolarization front -- dip region -- magnetosonic wave; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL068033
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Dipolarization front (DF) is a thin magnetic structure embedded in fast flows in the magnetotail, which plays an important role in particle acceleration, flow braking, wave excitation, and other related processes. Electromagnetic disturbances near the magnetic dip region in front of DFs are investigated using Time History of Events and Macroscale Interactions during Substorms probe observations in this paper. Strong magnetic field and electric field fluctuations, with several wave bands below and around the lower hybrid frequency, are found in an event on 21 March 2008. The properties of the wave are similar to that of magnetosonic wave. Detailed analyses show that the phase space density for ions in the perpendicular direction has a positive slope near the local Alfvén speed, which is a possible free‐energy source for the generation of the wave. This type of ion distribution could result from the earthward reflected ions ahead of DF, though other forming mechanism could not be fully ruled out. Key Points: Magnetosonic waves are observed near the dip region ahead of dipolarization front This wave is generated by ion perpendicular velocity distribution This type of ion distribution could be formed by the reflected ions ahead of DF