JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM13] [EE] Exploring space plasma processes with Magnetospheric Multiscale (MMS) mission

Sat. May 20, 2017 10:45 AM - 12:15 PM 105 (International Conference Hall 1F)

convener:Hiroshi Hasegawa(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Thomas Earle Moore(NASA Goddard Space Flight Ctr), Benoit Lavraud(IRAP), Seiji Zenitani(NAOJ National Astronomical Observatory of Japan), Chairperson:Seiji Zenitani(NAOJ National Astronomical Observatory of Japan)

11:30 AM - 11:45 AM

[PEM13-10] Global observations of high-m poloidal waves in the magnetosphere during the recovery phase of the June 2015 magnetic storm

*Guan Le1, Peter Chi2, Robert J Strangeway2, Christopher T Russell2, James Slavin3, Kazue Takahashi4, Howard Singer5, Vassilis Angelopoulos2, Brain Anderson4, Kenneth Bromund1, David Fischer6, Emil Kepko1, Werner Magnes6, Rumi Nakamura6, Ferdinand Plaschke6, Roy Torbert7 (1.NASA Goddard Space Flight Center, USA, 2.University of California, Los Angeles, USA, 3.University of Michigan, USA, 4.The Johns Hopkins University Applied Physics Laboratory, USA, 5.National Oceanic and Atmospheric Administration/SEC, USA, 6.Space Reserach Institute, Austrian Academy of Sciences, Austria, 7.University of New Hampshire, USA )

Keywords:Magnetospheric ULF Waves, High-m Poloidal Waves, Magnetospheric Multiscale Mission, Magnetic Storms

In this paper, we report global observations of high-m poloidal waves occurred during the recovery phase of the magnetic storm starting on 22 June 2015. The long lasting waves are observed by a constellation of widely spaced satellites from 5 missions including MMS, Van Allen Probes, THEMIS, Cluster, and GOES, covering L-values between 4 and 12 in a large range of local times. These observations have demonstrated that storm-time high-m poloidal waves can occur globally. High-resolution data from four MMS satellites enable us to detect the azimuthal phase shifts and determine the m number to be ∼ 100. The mode identification suggests that the observed poloidal waves are associated with the second harmonic of the field line resonance. The wave frequencies range from 8 to 22 mHz and decrease as the L-value increases. Detailed examinations of instantaneous wave frequency show discrete spatial structures with step-like changes along the radial direction. In each discrete structure the wave has a steady frequency and spans about 1 Re in the radial direction. Our observations suggest that storm-time high-m poloidal waves are different from the single-frequency global poloidal mode waves that are common during periods of low-level of geomagnetic activities.