Three-Dimensional Modeling of High- Latitude Scintillation Alex T. - - PowerPoint PPT Presentation

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three dimensional modeling of high latitude scintillation
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Three-Dimensional Modeling of High- Latitude Scintillation Alex T. - - PowerPoint PPT Presentation

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Three-Dimensional Modeling of High- Latitude Scintillation Alex T. Chartier 1 , Biagio Forte 2 , Kshitija B. Deshpande 3 , Gary S. Bust 1 1 Johns Hopkins University Applied Physics Laboratory 2 University of Bath 3 Virginia Tech Space Exploration

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Space Exploration

Three-Dimensional Modeling of High- Latitude Scintillation

Alex T. Chartier1, Biagio Forte2, Kshitija B. Deshpande3, Gary S. Bust1

1 Johns Hopkins University Applied Physics Laboratory 2 University of Bath 3 Virginia Tech

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Space Exploration

Outline

  • Observations
  • Modeling
  • Conclusions
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Space Exploration

Observations

  • Electron density profiles: EISCAT ISR Tromso
  • Small-scale structures: 50hz GPS receiver Tromso
  • Aurora: All-sky camera Ramfjordmoen (just south of Tromso)
  • Field-aligned currents: SuperMAG
  • Magnetosphere: THEMIS satellites
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Space Exploration

Radar Location Date: 17 October 2013, Time: 18:00 – 21:00 UT

Observations

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Space Exploration

Beam Direction Radar Location EISCAT tracks GPS satellite (PRN 23)

Observations

Date: 17 October 2013, Time: 18:00 – 21:00 UT

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Space Exploration

Observations: EISCAT

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Space Exploration

Observations: EISCAT

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Space Exploration

Observations: EISCAT + 50hz GPS

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Space Exploration

Tromso all-sky camera STELab Nagoya University

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Space Exploration

Tromso all-sky camera STELab Nagoya University

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Space Exploration

Poleward expansion

Tromso all-sky camera STELab Nagoya University

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Space Exploration

Tromso all-sky camera STELab Nagoya University

Poleward expansion

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Space Exploration

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Space Exploration

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Space Exploration

Westward Flow

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Space Exploration

Westward Flow

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Space Exploration

Westward Flow

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Space Exploration

Westward Flow

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Space Exploration

Themis satellite locations 20:05 UT

~8 earth radii

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Space Exploration

Themis 100 km footprints 20:05 UT

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Space Exploration

THEMIS P4

Electron Precipitation ~20:04 UT

18:00 UT 20:00 UT 22:00 UT 24:00 UT

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Space Exploration

THEMIS P4

EISCAT

Time (UT)

Electrostatic analyzer Search coil magnetometer 10 keV electron precipitation Solomon [2001]

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Space Exploration

Modeling

  • 3D multiple phase screen signal propagation [Rino, 1979].

60 phase screens, 5 x 5 x 400 km volume

  • 2 km cross-track gradient. 330 m/s drifts
  • Thick, anisotropic ionospheric irregularity layer [Costa &

Kelley, 1977]

  • Axial ratio: 5
  • Spectral index: 3
  • Outer scale: 5 km
  • SIGMA model implemented by Deshpande et al. [2014],

geometry modified here

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Space Exploration

Modeling

GPS receiver GPS signal

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Space Exploration

Modeling Refraction

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Space Exploration

Modeling Refraction Diffraction

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Space Exploration

Modeling

Parameter Value Cross-track velocity 330 m/s Gradient size 2 km Irregularities None Sample rate 10 Hz 18 seconds

EISCAT Observed Refractive Model

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Space Exploration

Modeling

Parameter Value Cross-track velocity 330 m/s Gradient size 2 km Irregularities 0.5 % Sample rate 10 Hz 18 seconds

EISCAT Observed Refractive + Diffractive Model

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Space Exploration

Summary

Substorm onset identified using GPS scintillation Three-dimensional modeling approach developed Refractive effects shown to be important

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Space Exploration

References

Costa, E., & Kelley, M. C. (1977). Ionospheric scintillation calculations based on in situ irregularity spectra. Radio Science, 12(5), 797-809. Deshpande, K. B., Bust, G. S., Clauer, C. R., Rino, C. L., & Carrano, C. S. (2014). Satellite‐beacon Ionospheric‐scintillation Global Model of the upper Atmosphere (SIGMA) I: High‐latitude sensitivity study of the model parameters.Journal of Geophysical Research: Space Physics, 119(5), 4026-4043. Rino, C. L. (1979). A power law phase screen model for ionospheric scintillation: 1. Weak scatter. Radio Science, 14(6), 1135-1145. Solomon, S. C. (2001), Auroral particle transport using Monte Carlo and hybrid methods, J. Geophys. Res., 106(A1), 107–116, doi:10.1029/2000JA002011.

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Space Exploration

SuperDARN

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Space Exploration

SuperDARN

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Space Exploration

SuperDARN

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Space Exploration

TEC modeling