WEBVTT FILE

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(music)

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Hi, I'm David

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Sibeck NASA's project scientist for the THEMIS mission. We're looking at

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results from a global simulation of the solar winds interaction

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with the earth's magnetic field. The sun is located far to the

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left, far outside the picture we're looking at. The Earth is the

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small blue dot, at the center of the cavity carved out by the

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Earth's magnetic field in the oncoming super sonic solar

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wind. The boundary to the left in the figure, is the magnetopause,

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the outer most reaches of the earth's magnetic field.

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The earth's magnetic field is buffeted by the solar wind, flapping back and forth,

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like a windsock in a gust of wind. Only a

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small fraction of the solar wind mass, momentum, and energy succeed

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in entering the earth's magnetic field. The process that controls that

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entry is magnetic reconnection. Reconnection takes energy

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away from the magnetic field and gives it to the particles in the

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plasma. The typical result of reconnection is high-speed flows,

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of energized particles streaming away from the reconnection site.

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The wispy white structures that you see, are regions where

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energy is being released from the magnetic field and converted into

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accelerated plasma flows. We're now looking at flows within the

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simulation. The arrows indicate the direction the plasma is moving with

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red, indicating flows at very high speeds. Within the magnetotail,

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on the right side of the picture we see that the arrows are associated

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with the wispy white regions where energy is being converted from

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the magnetic field, to the plasma, by reconnection. Now we're looking at a

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time later in the simulation. The sight of reconnection

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has moved far down the earth's magnetotail and is generating flows of

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plasma, that is arrows, that move to the left towards the

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earth, and towards the sun.

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(beeping)

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(beeping)

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