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Bell Tone

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Music

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Narrator: At first glance, these images might make you think that you had wandered into an

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art gallery. The truth is far more interesting. Although

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they look like impressionist-style paintings, they are actually made from data collected by

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the Solar Dynamics Observatory, or SDO, and show the heating and

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cooling of plasma in the sun's ultra-hot atmosphere.

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Dr. Nicholeen Viall: To produce these temperature change maps, we

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started with an interesting active region on the sun. We used data

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take with SDO's Atmospheric Imaging Assembly over a 24 hour

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period in 6 different wavelengths. Then we looked at these data

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one pixel at a time. By comparing the brightness of a pixel

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over time in two different wavelengths, we could tell if the plasma

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was heating up or cooling down, and then we could color-code it.

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A computer program ran this comparison over and over again

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for each pixel, 160,000 in all, and created a

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color map of how long the plasma to heat or cool.

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What we found was that most of the coronal plasma is in a

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state of cooling after having been rapidly heated by bursts of energy

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called nanoflares. We made these maps for many

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different wavelength combinations and different time periods. Since each

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wavelength represents a different temperature, this allows us to see how

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much the plasma is cooling down.

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Narrator: This creative and effective way of analyzing the incredibly complex behavior

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of the sun's atmosphere will help scientists gain greater understanding of why

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the corona is much hotter than the solar surface just beneath it.

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Music