Poloidal ULF wave observed in the plasmasphere boundary layer

doi:10.1002/jgra.50427

CORC > 北京大学 > 地球与空间科学学院

	Poloidal ULF wave observed in the plasmasphere boundary layer
	Liu, W. ; Cao, J. B. ; Li, X. ; Sarris, T. E. ; Zong, Q.G. ; Hartinger, M. ; Takahashi, K. ; Zhang, H. ; Shi, Q. Q. ; Angelopoulos, V.
刊名	journal of geophysical research space physics
	2013
关键词	ULF wave drift bounce resonance plasmasphere boundary layer STANDING ALFVEN WAVES RING CURRENT GEOMAGNETIC-PULSATIONS PARTICLE-POPULATIONS DIPOLE MAGNETOSPHERE STATISTICAL-ANALYSIS INNER MAGNETOSPHERE MOVING PLASMA FIELD LINES SOLAR-WIND
DOI	10.1002/jgra.50427
英文摘要	We report on a rare ultra-low-frequency (ULF) wave generation event associated with the formation of a plasmasphere boundary layer (PBL), which was well observed by one of the THEMIS satellites, TH-D, during subsequent outbound passes. On 13 September 2011, TH-D observed a sharp plasmapause at L=3.4. The plasmasphere started to expand and continued to be refilled on 14 September. On 15 September, a PBL was formed with two density gradients at L=4.4 and 6.5, respectively. Within the two density gradients, strong radial magnetic field and azimuthal electric field oscillations were observed, suggesting poloidal ULF waves. Based on the phase delay between magnetic and electric field signals, as well as the comparison between the observed wave frequency and predicted harmonic eigenfrequency, we find that the observed oscillations are second harmonic poloidal waves. Further investigation shows that the observed waves are likely generated by drift-bounce resonance with bump-on-tail plasma distributions at similar to 10keV. We demonstrate that the waves are excited within the PBL where the eigenfrequency is close to the bounce frequency of these hot protons, but not outside the PBL where the eigenfrequency deviates from the bounce frequency. Finally, we suggest that cold plasma density seems to be a controlling factor for ULF wave generation as well, in addition to the bump-on-tail energy source, by altering eigenfrequency of the local field lines.; Astronomy & Astrophysics; SCI(E); 3; ARTICLE; 7; 4298-4307; 118
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/222225]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Liu, W.,Cao, J. B.,Li, X.,et al. Poloidal ULF wave observed in the plasmasphere boundary layer[J]. journal of geophysical research space physics,2013.
APA	Liu, W..,Cao, J. B..,Li, X..,Sarris, T. E..,Zong, Q.G..,...&Angelopoulos, V..(2013).Poloidal ULF wave observed in the plasmasphere boundary layer.journal of geophysical research space physics.
MLA	Liu, W.,et al."Poloidal ULF wave observed in the plasmasphere boundary layer".journal of geophysical research space physics (2013).