University of Minnesota
School of Physics & Astronomy

Space Physics Seminar

Tuesday, November 21st 2017
12:20 pm:
Space Physics Seminar in Tate 301-20
Speaker: Aaron Breneman, University of Minnesota
Subject: Observations directly linking relativistic electron microbursts to whistler mode chorus: Van Allen Probes and FIREBIRD II

We present observations that provide the strongest evidence yet
that discrete whistler mode chorus packets cause relativistic electron microbursts.
On Jan 20th, 2016 near 1944 UT the low Earth orbiting CubeSat FIREBIRD
II observed energetic microbursts (near L=5.6 and MLT=10.5) from its lower
limit of 220 keV, to 1 MeV. In the outer radiation belt and magnetically conjugate,
Van Allen Probe A observed rising-tone, lower band chorus waves with
durations and cadences similar to the microbursts. No other waves were observed.
This is the first time that chorus and microbursts have been simultaneously observed
with a separation smaller than a chorus packet. A majority of the microbursts
do not have the energy dispersion expected for trapped electrons bouncing between
mirror points. This confirms that the electrons are rapidly (nonlinearly)
scattered into the loss cone by a coherent interaction with the large amplitude
(up to ∼900 pT) chorus. Comparison of observed time-averaged microburst flux
and estimated total electron drift shell content at L=5.6 indicate that microbursts may represent a significant source of energetic electron loss in the outer radiation
belt.

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