First Direct Experimental Measurement of loss cone scattering of energetic electrons by whistler

mode hiss in the plasmasphereVan Allen Probes/BARREL 2014 cooperative campaign.

EFW team: Aaron Breneman, John Wygant, John Bonnell, Scott Thaller, Kris Kersten and othersUniversity of Minnesota

BARREL team: Robyn Millan, Alexa Halford, Leslie Woodger, John Sample and othersDartmouth

EMFISIS team: Craig Kletzing, Scott Bounds, George Hospodarsky, Bill Kurth and others

MagEIS team: Joe Fennell

Quick Results

• First direct experimental verification that hiss causes e- loss in plasmasphere

• Surprise result:– Correlations occur

over LARGE regions and therefore have global effect on radiation belts.

~2 min period fluctuations

Quasi-linear diffusion calculationAngular random walk distance in bounce period

50–100 keV e- will scatter 1◦ over 1 sec bounce period ∼when interacting with the observed hiss.

MagEIS flux at 8 deg PA channel has 90,000 e-/s/cm3/keV/sr at 50 keV. Scaling this to BARREL field-of-view mapped to mag eq for single bounce period we find 8x10^20 e-/s scattered into DLC

Balloon 2I observes roughly 1,000,000 e−/cm2/s for the 50-100 keV range. Scaling to field-of-view (circle of 100 km radius at 70 km) we find 3x 10^20 e−/s.

Theoretical precipitation flux closely matches observed flux!

Extended mission opportunity…or the Van Allen Probe/BARREL/MMS science triumvirate

• Is the source of global-scale coherence in ULF period fluctuations of hiss and x-rays generated external or internal to magnetosphere?

• Compare observations of:– BARREL x-rays from 2015 N hemisphere

campaign– Van Allen Probe hiss, density, Bo– MMS ULF period fluctuations in solar wind

# Conjunctions/(Hr_M

LT * L)

MLT

MLT

L L LLLL

BARREL & RBSP Extended Mission Conjunctions

• BARREL Extended Mission • Kiruna, Sweden• 5 Payloads• Turn-Around (August) 2015

• Balloons mostly Geostationary • Consider RBSP Extended Mission

• Nominal Orbit (No Change)Predicted 1Payload BARREL & RBSP Conjunctions

August 2015Kiruna, SwedenRBSP A FootPtRBSP B FootPt

• Conjunctions for 2 Week Mission (Aug. 10-24, 2015) • Conjunction – Any time a RBSP

satellite is in same 1Hr by 1 L-value bin with a single BARREL balloon per hour UT time

• Conjunctions on Dayside Dusk sector mostly occur near Apogee

• Separation of Payloads at Apogee could increase conjunction duration

BARREL & RBSP Extended Mission Conjunctions

• Larger separation at apogee could provided extended time period of conjunctions with satellites on either side of payload

2015/08/18 12:00 VAPAVAPB

2015/08/18 12:00 VAPAVAPB

2015/08/18 12:00 VAPAVAPB

2015/08/18 12:00 VAPAVAPB

Nominal Orbit (No Change) Increase Delta Apogee by 200% Increase Delta Apogee by 300% Increase Delta Apogee by 200%, Decrease VAP A Perigee by 25 km

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