THEMISand

the Amazing Magnetic Flux Rope

D. G. Sibeck

Project Scientist

NASA/Goddard Space Flight Center

Where does the energy come from that drives the polar aurora?

Sun and Magnetosphere

We want to testing advanced numerical simulations

Looped Simulation from Nick Omidi:

Shows generation of FTE bulges/blobs moving antisunward from points of origin near the subsolar point.

Are they real?

Flux Ropes or Boundary Waves?

Let THEMIS-the blindfoldedGreek goddessof impartial justice decide!

Flux ropes Boundary wavesbulge outward bulge one wayin both directions or the other

AEDCB AEDCB

Observation and Interpretation

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THEMIS May 20, 2007

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Magnetosphere

Magnetosheath

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Dusk MP

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We used the 5 THEMIS spacecraftto construct cross-sections indicatinga flux rope detached from themagnetosphere

Flux Ropes Power the Magnetosphere!

1,500,000Amps

30 kiloVolt battery in space

1 Earth Radius

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Flux ropepumps650,000Amp currentinto the arctic!

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Summary

• 1. We used the 5 THEMIS spacecraft to identify a giant magnetic flux rope at the outer boundary of the Earth’s magnetic field.

• 2. We showed that the flux rope was detached from the magnetopause.

• 3. Flux ropes like this one apply 30 kiloVolts to the Earth and drives 650,000 amp currents into the polar cap.