First mission to ‘touch' the sun catches the solar wind

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Solar mission, which has been circling the sun in an attempt to uncover its secrets, has come close enough to the surface of our star to make a significant discovery.

The Parker Solar Probe's data has revealed the source of the solar wind. This is a stream of charged particles flowing from the corona (the hot outer atmosphere of the sun) toward Earth.

The mission named after the late astrophysicist Eugene Parker, and launched in 2018 was primarily motivated by the desire to understand how the wind forms near the Sun and escapes its gravity.

The probe's instruments captured details of the solar wind near the photosphere or solar surface. These fine structures will disappear when the wind blasts out of the corona.

It was designed to fly as close as 4 million miles (6,4 million kilometers) to the surface of the sun. In late 2021 it was the first mission that 'touched' the Sun.

Nature published a study Wednesday detailing solar findings.

Untangling solar wind

Solar wind is the continuous flow of plasma containing charged particles such as protons and electrons. This far-reaching phenomena also includes a part of the magnetic field of the sun and extends beyond the corona. It interacts with planets and interstellar material.

Two types of wind exist. Solar wind speeds up to 497 miles per hour (800 km per hour) from the holes in the corona near the poles of the sun. The slower solar winds, which are located on the same plane as Earth in the solar system, flow at a more calmer speed of 249 miles per seconds (400 kilometers per minute).

Solar winds are usually not fast enough to impact Earth. During the maximum of a solar cycle, a period of 11 years during which the sun gradually increases its activity, the magnetic field of the sun flips. The coronal holes appear on the surface of the sun and solar wind is released directly to Earth.

Scientists can better predict solar storms and space weather by understanding the origin of solar wind.

Solar storms are not only beautiful, but they can also have a negative impact on satellites and the Earth's electrical grid.

In a press release, James Drake, distinguished professor of Physics at the University of Maryland College Park, said that understanding the mechanism of the sun's winds is important to Earth for practical reasons. This will affect our understanding of how the sun releases its energy and creates geomagnetic disturbances that threaten our communication systems.

Data from the spacecraft revealed that coronal holes behave like showerheads. Jets appear as bright spots on the surface of the sun, indicating where the magnetic fields enter and exit the photosphere.

Magnetic fields break and reconnect as they pass in opposite directions, within these funnels, on the surface of the sun. This sends charged particles out the sun.

In a press release, Stuart D. Bale - a professor of Physics at the University of California in Berkeley - said that the photosphere was covered with convection cells.

Where these supergranulations cells meet and move downward, they drag magnetic fields in their path to this funnel-like downward type. There, the magnetic field is very intense because it is jammed. This is like a scooping of magnetic field into a drain. We can see the spatial separation between these little funnels and drains in solar probe data.

Parker Solar Probe detected highly-energetic particles that traveled between 10 and hundred times faster than solar wind. This led the researchers to believe the fast solar winds are created by reconnection magnetic fields.

Bale stated that the magnetic reconnection in these funnel structures is the source of energy for the fast solar winds. It's not just everywhere in the coronal hole. It's substructured inside coronal holes, to these supergranulation cell. These little bundles are magnetic energy associated with convection flow. We think that our results are a strong indication that reconnection is the cause.

The solar cycle

In July 2025 the sun will reach its solar maximum. This is why solar flares, northern and southern lights are being seen in unexpected locations. Parker Solar Probe, as well as a separate mission called Solar Orbiter are in a perfect position to observe these powerful and dynamic forces.

Scientists are thankful that Parker Solar Probe was launched before the sun's dramatic increase during the quieter Solar Minimum, when chaos could not have obscured observations.

Bale stated that there was some concern at the start of the mission when we were launching this thing into the quietest and dullest part of the cycle. But I don't think we would have known what was going on without it. It would have just been too messy. We're lucky to have launched it during the solar minimum.