Solar orbiter’s first science data shows the sun at its quietest

Quiet sun [image credit: NASA]

They picked an interesting time to study the Sun, as it starts to emerge from an unusually deep and long-lasting solar minimum. What effect this might have on Earth’s weather systems of course remains to be seen, but could be hard to quantify. The researchers have a lot of data to work through, and are hoping for ‘unprecedented insights into the sun’.
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Three of the Solar Orbiter spacecraft’s instruments, including Imperial’s magnetometer, have released their first data, reports Phys.org.

The European Space Agency’s Solar Orbiter spacecraft launched in February 2020 on its mission to study the sun and it began collecting science data in June.

Now, three of its ten instruments have released their first tranche of data, revealing the state of the sun in a ‘quiet’ phase.

The sun is known to follow an 11-year cycle of sunspot activity and is currently almost completely free of sunspots.

This is expected to change over the coming years as sunspot activity ramps up, causing the sun to become more active and raising the chances of adverse ‘space weather’ events, where the sun releases huge amounts of material and energy in solar flares and coronal mass ejections.

The sun’s activity is closely linked to the state of its magnetic field, and this is measured by Imperial’s instrument aboard Solar Orbiter, the magnetometer (MAG). Since June, MAG has recorded hundreds of millions of ‘vectors’ – measurements of the direction and strength of the sun’s magnetic field.

Solar Orbiter has already flown inside the orbit of Venus, collecting some of the closest data to the sun so far, and will get progressively closer in the coming years. It is currently orbiting close to the equator of the sun, which in times of high activity would show a very warped magnetic field.

Currently, however, the sun’s magnetic ‘equator’ is lying very flat to the true equator, allowing the spacecraft to observe fields from the Northern magnetic hemisphere for weeks on end, when just a few degrees north of the equator.

Near times of high solar activity, when the sun’s magnetic equator is more warped, it is not possible to see a single polarity of magnetic field for so long.

Solar wind structure

The MAG has also observed waves caused by protons and electrons streaming from the sun. Further out, near the Earth, these particles are distributed more evenly in the bulk solar wind of charged particles streaming from the sun, but at Solar Orbiter there are also ‘beams’ protons and electrons coming from the sun.

There appears to much more structure in the solar wind closer to the sun, and this is further shown by MAG confirming the presence of ‘switchbacks’ – dramatic folds in the solar wind first recorded by the Parker Solar Probe, a NASA mission launched in 2018.

Solar Orbiter and Parker Solar Probe will work together over the coming years to compare data on the same phenomena at different distances and orbits around the sun as it wakes up and enters the next phase of its sunspot cycle.

Full report here.

via Tallbloke’s Talkshop

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October 1, 2020 at 03:46AM

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