NASA’s Parker Solar Probe Reveals Origin of High-Speed Solar Winds

By Sarnith Varun

June 8, 2023
parker solar probe amid intense solar winds

NASA’s Parker Solar Probe, a space probe designed solely to study the sun and its Corona, not the disease, nor the beverage, we are talking about the outermost layer of the sun, may have found the origin of the high-speed solar wind shooting out of the Corona.1

What are Solar Winds?

The solar wind is a continual stream of protons and electrons from the sun’s outermost atmosphere — the corona. 

How are Solar Winds formed?

As the Sun rotates (once every 27 earth-days), it winds up its magnetic field lines above its polar regions into a large rotating spiral, creating a constant stream of “wind.” 

The Solar Wind is a turbulent stream of plasma, consisting of electrons and ions, flowing from the sun through Coronal Holes.

What are Coronal Holes?

A coronal hole is a temporary region of relatively cool, less dense plasma in the solar corona where the Sun’s magnetic field extends into interplanetary space as an open field.

These solar winds have two speeds termed “fast” and “slow”, the “slow” solar wind has a speed of ≈400 Km/s and the “fast” wind has a speed of ≈750 km/s, at the poles.

To put things in perspective, one of the fastest Fighter jets, the F22 Raptor has a speed of 1500 mph(0.67056 km/s).

Explanation of the High-Speed Solar Winds

High-Speed Solar Wind is said to be caused by switchbacks, an event where there is an abrupt change in the direction of the magnetic field, and the magnetic field suddenly reverses its direction over relatively short distances.

Within these switchbacks, there are kinks, which refer to bends or twists in the magnetic field lines. 

According to the research, these high-speed Solar winds are due to the newly reconnected field lines which exhibit sharper, pronounced switchbacks, it releases more energy potentially, due to the high stored energy during the reconnection process, termed interchange reconnection

Another possibility theorized is the acceleration by electromagnetic waves called Alfvén waves, which are generated in coronal holes through the interaction between convective flows and magnetic fields.

What is Convective flow?

Hot plasma rises from the core towards the surface, where it cools and sinks back towards the core.

However, recent research by the Parker Solar Probe suggests that the high-speed particles observed, are more likely a result of interchange reconnection rather than Alfvén wave acceleration as this aligns with the data from Parker.

The probe’s readings, when it was within 8.5 Million Kilometers of the Sun, in November 2021, gave us the closest look yet at how the fast solar wind is generated.

This suggests that a specific type of magnetic reconnection is what drives this powerful force of nature, according to a team of physicists led by Stuart Bale of the University of California, Berkeley, and James Drake of the University of Maryland, College Park.

That’s going to affect our ability to understand how the Sun releases energy and drives geomagnetic storms, which are a threat to our communication networks.

Explains James Drake

Why is Solar Wind Research Important?

Auroras in the Poles are famous worldwide, it is simply breathtakingly beautiful. 

If you have ever wondered how this scintillating phenomenon occurs, it is because of Solar winds. 

When the Solar wind reaches Earth, its charged particles distributed along the Earth’s magnetosphere, interact with Earth’s atmosphere and create beautiful glowing lights called auroras in the polar regions.

Solar winds are notorious for disrupting communications on Earth and posing a threat to astronauts. 

These winds have a significant impact on space weather, understanding solar wind behavior helps in predicting and solving potential disruptions caused by space weather events. 

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It is also important for future space exploration, for example, in designing protective measures for spacecraft, planning trajectories, and ensuring the safety of astronauts during space missions.

References

  1. Stuart Bale et al., ‘Interchange reconnection as the source of the fast solar wind within coronal holes’, Nature, 7 June 2023, “The fast solar wind that fills the heliosphere originates from deep within regions of open magnetic field on the Sun called ‘coronal holes’.”, https://www.nature.com/articles/s41586-023-05955-3#author-information[]
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