Inner Magnetospheric Shielding, Penetration Electric Field, and the Plasmasphere
First Direct Experimental Measurement of loss cone scattering of energetic electrons by whistler...
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Transcript of First Direct Experimental Measurement of loss cone scattering of energetic electrons by whistler...
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
• asdf