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Ultralow Frequency Waves Deep Inside the Inner Magnetosphere Driven by Dipolarizing Flux Bundles
Author(s) -
Liu Jiang,
Angelopoulos V.,
Zhang X.J.,
Runov A.,
Artemyev A.,
Plaschke F.,
Fu Song,
Lu San,
Liu YiHsin,
Chu Xiangning
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2017ja024270
Subject(s) - magnetosphere , physics , poynting vector , geophysics , van allen probes , flux (metallurgy) , plasma sheet , plasmasphere , energy flux , van allen radiation belt , computational physics , plasma , magnetic field , astronomy , materials science , metallurgy , quantum mechanics
Dipolarizing flux bundles (DFBs) are small flux tubes (typical cross‐tail scale of 1–3 R E ) in the nightside magnetosphere that have magnetic field more dipolar than the background. They are generated at or beyond 20 R E downtail and then travel earthward. Although DFBs usually stop before reaching the geosynchronous orbit (GEO), they may still transfer some portion of their energy into the inner magnetosphere by radiating ULF waves. We show the clearest evidence of this process, to date, using in situ data from a fleet of spacecraft and ground stations. We illustrate that a typical DFB stopped before reaching GEO but excited Pi2 waves that filled a volume of space extending from the plasma sheet to deep inside the plasmasphere. This event provides the first in situ, direct link between stopped DFBs and ULF waves deep inside the inner magnetosphere (as deep as L = 3). The waves were attenuated when traveling away from the DFB, but even at L = 3 ( X GSM = −2.2), they were still traveling with a significant earthward Poynting flux. In addition, we observed evidence of interaction between these waves and electrons at GEO.