RBSP SWG Meeting 1 3/5/2009

BARREL Update(Balloon Array for RBSP Relativistic Electron Losses)

R. M. Millan

and the

BARREL Team

RBSP SWG Meeting 2 3/5/2009

BARREL project overview

• Two Antarctic science campaigns during RBSP mission– 20 balloon launched each campaign in 2012 and 2013– Launched successively to set up slowly drifting array – LDB flights => ~30 day campaign duration

– >3000 hours of data in radiation belt region (L<7)– Launch sites: South African Antarctic Station (SANAE) and

Halley Bay

• Phase B test flights – Piggyback flight in December 2008– Test campaign from McMurdo in December 2009

BARREL is a multiple-balloon experiment designed to study relativistic electron precipitation.

BARREL is a multiple-balloon experiment designed to study relativistic electron precipitation.

RBSP SWG Meeting 3 3/5/2009

BARREL concept

• Launch Sites– SANAE IV– Halley Bay

BARREL uses an array of balloons to achieve its science objectives.

RBSP SWG Meeting 4 3/5/2009

Balloon observations of precipitation

• Bremsstrahlung X-rays are produced as precipitating electrons collide with atmospheric neutrals

• First observation of X-rays to MeV energies made in 1996 over Kiruna, Sweden.• Nearly stationary balloon platform => complementary to spacecraft measurements

(Foat et al., 1998)

~30 km

~70 km

RBSP SWG Meeting 5 3/5/2009

Kiruna REP Event

(from Lorentzen, 1999)

Riometer

X-ray instrument

RBSP SWG Meeting 6 3/5/2009

RBSP/Balloon Conjunctions

• Baseline: two campaigns separated by one year– Measurements of BOTH microbursts and duskside

precipitation during both camaigns.

Conjunctions with RBSP spacecraft in dusk and dawn sectors

Dusk conjunctions in 2012

Dawn conjunctions in 2013

BARREL MLT

Hou

rsH

ours

RBSP SWG Meeting 7 3/5/2009

Large-scale spatial structureS2

S3

X-ray count rate

Balloon locations

~800km separation

• Precipitation simultaneously observed by two balloons on January 21, 2005

L=3.5

L=4L=6

18MLT 6 MLT18 MLT

1840 UT

L=4L=6

18MLT 6 MLT18 MLT

1845 UT

RBSP SWG Meeting 9 3/5/2009

BARREL project overview

• Two Antarctic science campaigns during RBSP mission– 20 balloon launched each campaign in 2012 and 2013– Launched successively to set up slowly drifting array – LDB flights => ~30 day campaign duration

– >3000 hours of data in radiation belt region (L<7)– Launch sites: South African Antarctic Station (SANAE) and

Halley Bay

• Phase B test flights – Piggyback flight in December 2008– Test campaign from McMurdo in December 2009

RBSP SWG Meeting 10 3/5/2009

2009 Piggyback Test Flight

RBSP SWG Meeting 11 3/5/2009

2008/2009 Piggyback Test Flight

Launch: McMurdo, Dec. 28, 2008Duration: 54 daysAltitude: 34 km (112 kft)

Photo Courtesy D. GregoryNASA BPO

RBSP SWG Meeting 12 3/5/2009

Summary Plot: X-ray Count Rate

RBSP SWG Meeting 13 3/5/2009

Summary Plot: X-ray Count Rate

Relativistic PrecipitationRelativistic Precipitation

RBSP SWG Meeting 14 3/5/2009

~10-100 keV Precipitation Event

X-ray Count Rate

9:00 UT9:00 UT

RBSP SWG Meeting 15 3/5/2009

BARREL LocationBARREL Location

THEMIS spacecraft at 9:00 UT

TIPSOD

RBSP SWG Meeting 16 3/5/2009

THEMIS AE IndexTHEMIS AE Index

SST electronsSST electrons

Electric FieldElectric Field

THEMIS Data on Jan. 3, 2009

RBSP SWG Meeting 17 3/5/2009

Feb 14-15, 2009

X-ray SpectrumX-ray Spectrum

Cou

nts/

sC

ount

s/s

Energy (keV)Energy (keV)

RBSP SWG Meeting 18 3/5/2009

WHAT’S NEXT?

• Two Antarctic science campaigns during RBSP mission– 20 balloon launched each campaign in 2012 and 2013– Launched successively to set up slowly drifting array – LDB flights => ~30 day campaign duration

– >3000 hours of data in radiation belt region (L<7)– Launch sites: South African Antarctic Station (SANAE) and

Halley Bay

• Phase B test flights – Piggyback flight in December 2008– Test campaign from McMurdo in December 2009

RBSP SWG Meeting 19 3/5/2009

2009/2010 Test Campaign

• Currently building hardware for 6 payloads. • Integration at Dartmouth starts at end of this month• Thermal Vac and test launch in Palestine, TX summer 2009• Deploy to Antarctica November 2009

RBSP SWG Meeting 20 3/5/2009

Objectives of BARREL with RBSP

• Directly test models of wave-particle interactions.– Conjunctions between balloons and RBSP spacecraft

=> measurements of parameters needed to model interaction

– Comparison of predicted and observed precipitating flux and energy distribution

• Large-scale spatial structure and total loss rate estimates.– What are the most useful data products or methods

for displaying data?

RBSP SWG Meeting 21 3/5/2009

Cold plasma 50 cm-3, 1 eV

Magnetic Field 170 nT

Composition 85% H, 10% He, 5% O

Hot Protons:

Density -----

Energy -----

Tperp/T// ----

1 cm-3

12 keV

1.47

•Input parameters for WHAMP during the Jan. 19, 2000 precipitation event. Parameters are mean values taken from LANL MPA, except magnetic field taken from IGRF and plasma composition which was taken from Meredith et al., (2003).

•WHAMP calculation of the wave frequency for three branches of EMIC waves

ω/o

meg

ai

k k

ωim

agin

ary /

omeg

ai

Modeling EMIC Wave Growth

RBSP SWG Meeting 22 3/5/2009

Barrel Primary Science Teams

University of WashingtonNaI ScintillatorFlight Computer

UC Berkeley-SSLPower SystemMission AssuranceSE oversight

GSFC + Balloon Program OfficeProgrammatic, Management oversight

CSBFMIPLaunch Training

UC Santa CruzMagnetometerGround Station

Dartmouth CollegePI-InstitutionSystems EngineeringEngineering DataIntegration & Test

RBSP SWG Meeting 23 3/5/2009