Quirks & Quarks

NASA's mission to touch the sun reveals 'rogue waves' and flipping magnetic fields

First results from the mission might help explain how the sun's atmosphere reaches such extreme temperatures

Launched in 2018, the spacecraft has flown closer to the sun than any other mission

An artist's concept of NASA's Parker Solar Probe observing the sun. (NASA/Johns Hopkins APL/Steve Gribben)

The first batch of research from NASA's Parker Solar Probe mission that was announced recently reveals intense "rogue waves" in the sun's atmosphere.

This new form of high energy waves might help explain the longstanding mystery of how the sun's atmosphere is able to reach extreme temperatures of millions of degrees.

The Parker Solar Probe is NASA's ambitious mission to "touch the star." Launched in August 2018, it was designed to enter the outer atmosphere or the corona of the sun, in order to get closer to the star than any probe has ever done before. 

"It's the largest helium physics mission NASA has ever undertaken and one of its main objectives is to figure out why the sun's corona is about a thousand times hotter than the surface of the sun," Justin Kasper told Quirks & Quarks host Bob McDonald in an interview. 

The other objective is to figure out how the corona generates high speed solar winds that travel millions of kilometres per hour through space, threatening astronauts and communication devices with its ionized particle streams.

Kasper, one of the principal investigators on NASA's Parker Solar Probe and a professor of space sciences and engineering at the University of Michigan, said his research involves counting how many ions and electrons make up the solar atmosphere and solar winds in order to better understand solar wind speed, temperature, and the density of particles inside the corona. 

So far, the probe has managed to approach within 35 solar radii of the sun — twice as close as previous probes have gotten. It's collected preliminary data during its first two encounters with the sun for scientists back on Earth.

In the next few years, the probe will continue to make orbits around the sun, each time using Venus's gravity to get it closer to the giant star until it's within 10 solar radii, or approximately seven million kilometres from the sun. That's the distance in which the probe will cross the critical Alfvén point in the sun's outer atmosphere, where we can officially say that it has "touched" the star. 

'Rogue waves' could be behind the corona's extremely high temperature 

Kasper has spotted a new type of high-speed "rogue waves" flying through solar winds in the sun's corona in the initial data collected by the probe,

"The spacecraft would be coasting along through the solar wind, and then suddenly within seconds, the speed of the flow would jump by about 500,000 kilometres an hour, and we'd be sitting there in this weird jet of flow," Kasper explained. 

An image taken from Parker Solar Probe’s WISPR (Wide-Field Imager for Solar Probe) instrument shows a coronal streamer structure. (NASA)

Just as suddenly as it arrived, a few seconds later, the stream would leave and the probe would pop out the other side. 

Kasper analyzed the data and found that the waves were behaving in violent and strange new ways that scientists have never seen before. 

"It's so violent that it's actually twisting the sun's magnetic field around itself," he said. This made him think it could be a major source of energy for heating the corona. 

The waves were shredding themselves apart, and the jump in velocity was too violent to be stable, according to Kasper. This could be a possible mechanism for these waves to be losing energy, which would explain the corona's extremely high temperature, he conjectured, but we would need more encounters with the sun to test the theory to make sure we're not passing a very special region of the sun this time.

There's so much we still don't know about the sun 

Another major finding gleaned from the data pertains to space weather. The solar corona ejects massive amounts of plasma material travelling at an extremely high speed that's roughly equivalent to the water in Lake Michigan going from rest to motion at a few million kilometres per second in just minutes, Kasper said. 

The incredible amount of energy this generates when the material passes by Earth is a huge threat to our astronauts and communication systems in space and power grids. As a result, scientists hope to better forecast these violent coronal mass ejections and its impact on Earth. 

This shows us that we're still missing fundamental knowledge about how objects circulate near the sun.- Justin Kasper

To Kasper's surprise, analysis of the initial data collected from the probe shows that the sun's atmosphere is spinning faster near the centre layer than the outer edges, contrary to what researchers thought.

Our current solar weather model assumes the opposite, said Kasper. This new finding might explain why our current solar weather model doesn't work well.

"This shows us that we're still missing fundamental knowledge about how objects circulate near the sun," said Kasper.

"We still need to better understand a lot of the things about the sun."