Small Satellite Constellations for Space Weather Research and Forecasting

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R. Robinson¹, D. Rowland², K. Garcia-Sage², L. Kepko²

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¹The Catholic University of America

²NASA Goddard Space Flight Center

SSWRF

AMPERE uses magnetometer data from the Iridium constellation

of 66 satellites to measure field-aligned currents globally and continuously.

Iridium

(AMPERE)

TIMED (400,000 measurements from GUVI)

5880 measurements from the Poker Flat Incoherent Scatter Radar (PFISR)

• Electron Density Profile->Conductivity
• FUV Luminosity->Energy flux
• Field-aligned currents

Measurements of auroral energy flux and conductances in conjunction with AMPERE measurements of field-aligned currents

AMPERE-Derived ELectrodynamic Properties of the High-latitude Ionosphere

(ADELPHI)

Energy Flux

Electric Field

Horizontal Currents

Joule heating

Conductivities

Field-aligned Currents

Global Parameters

HPI Precipitation

Cross

Polar Cap Potential

HPI

Joule Heating

Magnetic Indices

Weimer, D. R., N. C. Maynard, W. J. Burke, and C. Liebrecht (1990), Polar cap 637 potentials and the auroral electrojet indices, Planet. and Space Sci., 38, Issue 9, pp. 638 1207-1222, https://doi.org/10.1016/0032-0633(90)90028-O. 

From Østgaard et al. (2002)

Cons and Pros

• The Iridium magnetometers are not ‘scientific’ quality instruments.
• The telemetry rate limits the inherent temporal/spatial resolution of the measurements.
• Gaps in coverage are filled using a spherical harmonic fitting technique.
• The global coverage and continuous data stream compensates for many of the inherent shortcomings of the measurements and data analysis techniques.
• Constellations allow for trade-offs between data quality and space weather product utility for both research and applications.

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GDC will reveal the upper atmospheric pathways of energy and momentum transport

GDC will measure drivers and responses of the Ionosphere-Thermosphere system:

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Drivers Responses

Electric Fields Ion Drift

Magnetic Fields Neutral Wind

Precipitating electrons and ions Neutral and plasma density, temperature,

and composition

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GDC samples at all scales, local times, and seasons over its 3-year mission

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10/2/22

”Local” phase

”Regional” phase

”Global” phase

GDC Observing System Simulations Experiments

• AMPERE-Derived Electrodynamics of the High-latitude Ionosphere (ADELPHI) model for ground truth:
• Precipitating particle energy flux
• Conductances
• Electric potential and electric fields
• Currents
• Joule heating
• Global Ionosphere Thermosphere Model (GITM) for ground truth:
• Neutral density
• Electron density

Actual and Reconstructed Hemispherically Integrated Joule Heating

13 October 2016

GITM Neutral Density + TADs 7 March 2015 0540 – 0800 UT

Reconstructed Neutral Density 7 March 2015 0540 – 0800 UT

Lessons Learned from GDC and AMPERE

• The ability to characterize spatially and temporally varying phenomena often depends on fortuitous locations of spacecraft in the constellation during any particular event
• Continuous mapping of reconstructed parameters from the constellation captures global variability during all mission phases
• The complex temporal and spatial sampling provided by the constellation allows for ‘tomographic’ inversion to detect dynamic structures
• The same analysis techniques needed to extract information from constellation data are very much the same as those needed to produce space weather products. I. e, the R2O process for constellations eliminates a step in going from a prototype system to and operational system.

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Advantages/Challenges of Constellations

• Spatial Coverage
• Global maps (“I’m feeling lucky”)
• Comparison with local observations
• Continuous time series
• Event/feature sampling
• Challenges
• Filling in gaps
• Deconvolution
• Optimization

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