quick results
Post on 01-Jan-2016
11 Views
Preview:
DESCRIPTION
TRANSCRIPT
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
top related