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First Direct Experimental Measurement of loss cone scattering of energetic electrons by whistler mode hiss in the plasmasphere Van Allen Probes/BARREL 2014 cooperative campaign. EFW team: Aaron Breneman, John Wygant , John Bonnell , Scott Thaller , Kris Kersten and others
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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 others University of Minnesota BARREL team: Robyn Millan, AlexaHalford, Leslie Woodger, John Sample and others Dartmouth 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 calculation Angular random walk distance in bounce period 50–100 keVe- 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 mageq 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
BARREL Extended Mission • Kiruna, Sweden • 5 Payloads • Turn-Around (August) 2015 • Balloons mostly Geostationary • Consider RBSP Extended Mission • Nominal Orbit (No Change) August 2015 Kiruna, Sweden RBSP A FootPt RBSP B FootPt BARREL & RBSP Extended Mission Conjunctions MLT Predicted 1Payload BARREL & RBSP Conjunctions # Conjunctions/(Hr_MLT * L) L L L L L L • 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 MLT
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 2015/08/18 12:00 2015/08/18 12:00 2015/08/18 12:00 VAPA VAPB VAPA VAPB VAPA VAPB VAPA VAPB Increase Delta Apogee by 200%, Decrease VAP A Perigee by 25 km Increase Delta Apogee by 300% Nominal Orbit (No Change) Increase Delta Apogee by 200%