Ionospheric electrodynamics low earth orbiting satellites leos
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Ionospheric Electrodynamics & Low-Earth Orbiting Satellites (LEOS). J-M No ë l, A. Russell, D. Burrell & S. Thorsteinson Royal Military College of Canada October 7 th , 2009 Ubatuba, Brazil. Outline. An extreme example of space weather

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Ionospheric Electrodynamics & Low-Earth Orbiting Satellites (LEOS)

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Ionospheric electrodynamics low earth orbiting satellites leos

Ionospheric Electrodynamics&Low-Earth Orbiting Satellites (LEOS)

J-M Noël, A. Russell, D. Burrell

&

S. Thorsteinson

Royal Military College of Canada

October 7th, 2009

Ubatuba, Brazil


Outline

Outline

  • An extreme example of space weather

    • Halloween 2003 Event and it’s effect on LEOs orbits.

  • Numerical models

    • Neutral atmosphere – HLTIM

    • Electrodynamic – Electro

    • Ionospheric – Transcar

  • Some numerical Results

  • Implications for satellite orbits

    • predictions

  • Concluding remarks


Most powerful solar flares ever recorded

Most Powerful Solar Flares Ever Recorded


Ionospheric electrodynamics low earth orbiting satellites leos

Altitude from the surface

CHAMP


Ionospheric electrodynamics low earth orbiting satellites leos

Altitude from the surface

Drop of ~300 m

in a few days

SCISAT 1


Ionospheric electrodynamics low earth orbiting satellites leos

Altitude ~ 390 km

Nov 9-11

2004 ??

July 29

2004 ??

May 28

2003 ??


Ionospheric electrodynamics low earth orbiting satellites leos

Altitude ~ 710 km


Satellite drag

Satellite Drag

  • adrag is the in-track acceleration (m/s2)

  • CD is the drag coefficient

  • vsat is the satellite velocity (m/s)

  • vn is the neutral wind (m/s)

  • A is the cross-sectional area (m2)

  • ρ is the neutral number density (m-3)


Drag coefficient c d

Drag Coefficient, CD

Moe and Moe, 2005

Average value that is used

for most satellites


What we want to study

What we want to study

  • Thermospheric responses to ionospheric electric fields.

    • Electric fields can vary substantially in both space and time.

  • How does the thermospheric responses affect satellite orbits?

    • Variation in CD, ρ and v (not just only ρ)

    • In this talk we will concentrate on ρ.


Tools

Tools


High resolution high latitude thermospheric model

High Resolution High Latitude Thermospheric Model

  • Thermospheric Model – A. T. Russell

    • based on the 2-D model of Chang and St.-Maurice (1991)

    • solves the Navier-Stokes equations

    • several upgrades have been incorporated into the model e.g. new cooling rates, stretched vertical grid, more realistic initial conditions.


Some numerical results

Some Numerical Results


Thermospheric response

Thermospheric Response

horizontal transport

vertical transport

  • A. T. Russell (2007), Russell et. al. (2007)


Satellite observations

Satellite Observations

Schlegel et al, Ann. Geophys., 2005


Champ observations

CHAMP Observations

Schlegel et al, Ann. Geophys., 2005


The end

The End

Liu et al., JGR 2005


Fac and neutral densities

FAC and Neutral Densities

Neubert & Christiansen, GRL, 2003

Liu et al., JGR 2005


Stk simulations of champ orbit the halloween event

STK Simulations of CHAMP OrbitThe Halloween Event


Basic assumptions

Basic Assumptions

  • Severe space weather simulation

    • large ambient electric field in the ionosphere-thermosphere, 100 mV/m, 0.5° half-width centered at 70°, ramped from 0 to 100 linearly in 1000 seconds.

  • Use MSIS as a base neutral atmosphere

    • Add density perturbations obtained from the thermospheric model (HLTIM – Russell)


Basic assumptions continued

Basic Assumptions – Continued

  • Assumed that the thermosphere is symmetric.

    • i.e. no variation in the East-West direction.

  • The latitudinal distribution is the same for the southern hemisphere as it is for the northern hemisphere.


Stk modeling of champ orbit october 26th 2003

STK Modeling of CHAMP Orbit October 26th, 2003

1200 to 1430, separation between sats ~ 20 meters


Modeling of champ orbit november 4 th 2003

Modeling of CHAMP Orbit November 4th, 2003

1000 to 1330separation of sats is ~250 km


Champ accelerations

CHAMP accelerations


Concluding remarks

Concluding Remarks

  • Space weather plays a important role in the decay rates of satellite orbits via:

    → increases in the electrodynamical response

    → increases frictional heating

    → increases the thermospheric densities in the vicinity of orbiting satellites.


Concluding remarks1

Concluding Remarks

  • Small-scale auroral structures having intense electrodynamics should not be neglected when simulating satellite orbits to determine their projected lifetimes.

  • We have made an attempt to simulate the effects of the small-scale structures on satellites for the first time.


What s next

What’s Next?

  • Complete the coupling of the thermospheric model:

    • Transcar – ionospheric model

      • Blelly et al., 1996

    • Electro – electrodynamic model

      • Noel et al., 2001, 2005

  • Comprehensive Coupled 2 – D Model

    • De Boer et al., 2009 submitted


Thank you obrigado

Thank YouObrigado


Steep precipitation pattern

Steep Precipitation Pattern


Electrodynamical response

Electrodynamical response

Noël, 2006


Ionospheric response

Ionospheric Response

Noël, 2006


More observations from champ

More observations from CHAMP


Thermospheric response1

Thermospheric Response

  • A. T. Russell (2005)


Halloween 2003

Halloween 2003 Event

Halloween 2003


Halloween 2003 event soho

Halloween 2003 EventSOHO


What we want to study1

What we want to study

  • Current systems and electric fields in the vicinity and inside auroral arcs

    • There are 2 kinds of FAC

      • FAC driven by the magnetosphere.

      • FAC associated with divergences in Pedersen currents.

        • They are known to produce FACs on the edges of arcs.

  • Electric Fields

  • Ionospheric and thermospheric responses.

  • How these responses affect satellite orbits.


Champ accelerations1

CHAMP accelerations


Champ accelerations2

CHAMP accelerations


Electrodynamic model electro

Electrodynamic Model (Electro)

  • 2-dimensional model based on divergence-free current density.

  • computes the electric potential, electric fields and current densities.

  • Noël, (1999), Noël et al. (2001, 2005)


Ionospheric model

Ionospheric Model

  • Transcar – transport (Blelly et al., 1996)

    • computes the time evolution of the ionosphere (composition, energetics and transport).

    • 1-dimensional along the magnetic field line.

    • electron energy spectrum

    • electron heating due to waves (Dimant and Milikh, (2003), Noel et al. (2005))


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