Details of Parker Solar Probe's groundbreaking discoveries about the Sun

Details of Parker Solar Probe's groundbreaking discoveries about the Sun

NASA's Parker Solar Probe surprised scientists with its groundbreaking views of the Sun as the first results from the mission were released on Wednesday, December 4, 2019. Scientists observed bursts of energetic particles never seen before on a small scale, and switchback-like reversals in the out-flowing solar magnetic field apparently whipping up the solar wind. The mission's goal is to shed light on the mysteries about the Sun.

"They’re striking and it’s hard to not think that they’re somehow important in the whole problem," said astrophysicist Stuart Bale and member of the mission team. Nicola Fox, director of NASA's heliophysics division, compared this unprecedented switchback phenomenon to the cracking of a whip.

Researchers said they also finally gathered evidence dust-free zone rotating around the Sun. Farther out, there is much more dust from vaporizing comets and asteroids that one of the 80 small viewfinders on a solar probe instrument was pierced by a grain.

"I can’t say that we don’t worry about the spacecraft. I mean, the spacecraft is going through an environment that we’ve never been before," Fox said.

When observed near Earth, the solar wind is a relatively uniform flow of plasma with occasional turbulent tumbles. However, closer to the solar wind's source, Parker Solar Probe caught a different picture-- a complicated, active system.

"The complexity was mind-blowing when we first started looking at the data," said Stuart Bale, the University of California, Berkeley, lead for Parker Solar Probe’s FIELDS instrument suite. "Now, I’ve gotten used to it. But when I show colleagues for the first time, they’re just blown away."

From Parker's vantage point 24 million km (15 million miles) from the Sun, the solar wind is much more impulsive and unstable than what people see near Earth.

The solar wind is made up of plasma, like the Sun itself, where negatively charged electrons have separated from positively charged ions. This creates a sea of free-floating particles with an individual electric charge.

The particles indicate that plasma carries electric and magnetic fields, and changes in the plasma often produce marks on the fields.

“Waves have been seen in the solar wind from the start of the space age, and we assumed that closer to the Sun the waves would get stronger, but we were not expecting to see them organize into these coherent structured velocity spikes," said University of Michigan' Justin Kasper, principal investigator for Solar Wind Electrons Alphas and Protons (SWEAP).

Another question that the probe addressed is how the solar wind flows out from the Sun. "Near-Earth, we see the solar wind flowing almost radially-- meaning it's streaming directly from the Sun, straight out in all directions," NASA wrote.

"But the Sun rotates as it releases the solar wind; before it breaks free, the solar wind was spinning along with it. This is a bit like children riding on a playground park carousel-- the atmosphere rotates with the Sun much like the outer part of the carousel rotates, but the farther you go from the center, the faster you are moving in space."

Parker Solar Probe was able to observe the solar wind while it was still rotating. Its solar wind instrument detected rotation starting more than 32 million km (20 million miles) from the Sun.

The speed of the rotation increased as Parker approached its perihelion point-- stronger than many scientists had anticipated. It also transitioned more quickly than predicted to an outward flow, which is what helps mask these effects from where we usually sit, about 150 million km (93 million miles) from the Sun.

"The large rotational flow of the solar wind seen during the first encounters has been a real surprise," said Kasper.

"While we hoped to eventually see rotational motion closer to the Sun, the high speeds we are seeing in these first encounters is nearly ten times larger than predicted by the standard models."

In addition, another question nearing to be answered is the elusive dust-free zone. For the first time, Parker imagers observed the cosmic dust that is starting to thin out. 

These images show dust starting to thin a little over 11 million km (7 million miles) from the Sun, and this decrease in dust continues steadily to the current limits of Wide-field Imager for Solar Probe's (WISPR) measurements at a little over 4 million miles from the Sun.

Parker Solar Probe's measurements have also provided a new perspective on two types of space weather events-- energetic particle storms and coronal mass ejections.

Parker Solar Probe's  Integrated Science Investigation of the Sun (ISʘIS) instruments have measured several never-before-seen energetic particle events-- events so small that all trace of them is lost before they reach Earth or any of our near-Earth satellites.

"Even at solar minimum conditions, the Sun produces many more tiny energetic particle events than we ever thought," said David McComas, principal investigator for the ISOIS suite at Princeton University.

"These measurements will help us unravel the sources, acceleration, and transport of solar energetic particles and ultimately better protect satellites and astronauts in the future."

Furthermore, data from the WISPR instruments gave detail on structures in the corona and solar wind,  including coronal mass ejections, billion-ton clouds of solar material that the Sun sends hurtling out into the solar system.

"Since Parker Solar Probe was matching the Sun's rotation, we could watch the outflow of material for days and see the evolution of structures," said Russ Howard, principal investigator for the WISPR suite.

"Observations near Earth have made us think that fine structures in the corona segue into a smooth flow, and we're finding out that's not true. This will help us do better modeling of how events travel between the Sun and Earth."

Parker is on course to sweep past Venus on December 26 for the second gravity-assist and make its fourth near solar encounter in January. The results were discussed in multiple studies in the Nature journal and were made during a quiet phase of solar activity.

"We’re just starting to scratch the surface of this fascinating physics," said Princeton University space plasma physicist David McComas, the chief scientist of one of the spacecraft’s instruments.

The Sun will go through an active phase as Parker comes nearer its target. "We can expect even more exciting results soon," said Daniel Verscharen of the University College London, who also studies the Sun but was not part of this particular mission.

Fox shared the results with astrophysicist Eugene Parker, professor emeritus at the University of Chicago for whom the spacecraft is named after.

References:

"Alfvenic velocity spikes and rotational flows in the near-Sun solar wind" - Kasper, J. C. et al - Nature - DOI: 10.1038/s41586-019-1813-z

Abstract

The prediction of a supersonic solar wind was first confirmed by spacecraft near Earth and later by spacecraft at heliocentric distances as small as 62 solar radii. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second—considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age.

"Highly structured slow solar wind emerging from an equatorial coronal hole" - Bale, S. D. et al - Nature - DOI: 10.1038/s41586-019-1818-7

Abstract

During the solar minimum, when the Sun is at its least active, the solar wind is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain, theories and observations suggest that they may originate at the tips of helmet streamer, from interchange reconnection near coronal hole boundaries, or within coronal holes with highly diverging magnetic fields. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvén-wave turbulence, heating by reconnection in nanoflares, ion cyclotron wave heating, and acceleration by thermal gradients. At a distance of one astronomical unit, the wind is mixed and evolved, and therefore much of the diagnostic structure of these sources and processes has been lost. Here we present observations from the Parker Solar Probe at 36 to 54 solar radii that show evidence of slow Alfvénic solar wind emerging from a small equatorial coronal hole. The measured magnetic field exhibits patches of large, intermittent reversals that are associated with jets of plasma and enhanced Poynting flux and that are interspersed in a smoother and less turbulent flow with a near-radial magnetic field. Furthermore, plasma-wave measurements suggest the existence of electron and ion velocity-space micro-instabilities that are associated with plasma heating and thermalization processes. Our measurements suggest that there is an impulsive mechanism associated with solar-wind energization and that micro-instabilities play a part in heating, and we provide evidence that low-latitude coronal holes are a key source of the slow solar wind.

Featured image credit: NASA/Johns Hopkins APL

Comments

Jamal Shrair 1 year ago

RIGHT NOW I AM THE HAPPIEST MAN IN THE WORLD. The latest data from Parker Solar Probe have further consolidated my proposed solar model. And, I would like to tell you, that the flipping back and forth of the magnetic fields that emanating from the Sun is in full agreement with my proposed model. It is not a mystery at all. It is the physical reality of the Sun. I am so happy and grateful to Parker Solar Probe. Another, extremely important evidence has just been added to the long list of observation facts that show the correctness of my model. "The most startling discovery the teams made was that magnetic fields emanating from our star seemed to unexpectedly flip back and forth, causing local disturbances — what scientists dubbed “switchbacks” — which can even cause them to point back at the Sun at times. The cause of these switchbacks is still a mystery to scientists, but they could eventually allow us to understand how energy flows away from the Sun and throughout the Solar System." https://futurism.com/scientists-new-data-nasa-solar-probe

Steve Edward 1 year ago

It appears the sun is not driven by thermonuclear activity. Rather, it appears the sun is driven by 'plasma activity.' And plasma is defined as..."a state of matter in which an ionized gaseous substance becomes highly electrically conductive to the point that long-range electric and magnetic fields dominate the behaviour of the matter. " Plasma (physics) - Wikipedia It appears the science purveyors of the electric 'sun theory' have been confirmed in their theories as far back as 2005. https://www.thunderbolts.info/wp/2011/12/05/considering-the-electric-sun-part-1/ Even further back in the early 20th century, The Norwegian physicist Kristian Birkeland (1867-1917) demonstrated the parallel behavior of plasma in a laboratory relative to the 'electric sun.' https://www-spof.gsfc.nasa.gov/Education/whaur1.html

Jamal Shrair 1 year ago

I DON'T KNOW IF I SHOULD LAUGH OR CRY! These data from Parker Solar probe do not convince you, "SOLAR AUTHORITY", that gravity is not the dominant force over the Sun? And, these data do not convince you that the high energy particles which are bombarding the solar atmosphere are the cause for the increase of the temperature of the corona and the increase in the speed of the ejected solar material? The experimental physics of electromagnetism can easily explain all the observed data that are obtained by Parker Solar Probe, and nothing else is needed. It is high time to give up the Standard Solar Dogma and acknowledge the physical reality of our own star. The amount of observational facts since, the start of the space age- that show the dogmatic nature of the current model are so huge and so convincing, even to the most stubborn minds. However, you are not missing one fundamental fact about the corona, Professor Kasper. You are missing, ALL THE BASIC FACTS ABOUT THE ENTIRE STRUCTURE OF THE SUN. I will be eternally grateful, if you can tell me a single observational study based on, advanced space telescope, which is in partial agreement with the notions of the standard solar model. Nevertheless, the model that represents the physical reality of the Sun exists, and I challenge any astrophysicist to tell me, one observation that cannot be explained by it. This model explains all phenomena and observed features, including why the area above and below the so-called tachocline varies its rotation in a regular pattern. By the way, this variation is the key for understanding how the sun's enormous magnetic fields are generated, and why they reverse polarity from positive to negative every 11-12 years. My proposed model also explains why the core rotates much faster than the surface and it also, solves the solar abundance problem, the missing neutrinos problem, which has not been solved since, no neutrinos are missing to start with ….etc. In addition to the above, the proposed model is the framework of how to reproduce the nuclear reaction responsible for its radiated energy, which is not thermonuclear reaction.

Jamal Shrair 1 year ago

DATA FROM PARKER SOLAR PROBE HAS GIVEN ME A NEW VICTORY OVER MAINSTREAM ASTROPHYSICISTS "Even with just these first orbits, we've been shocked by how different the corona is when observed up close," said Justin Kasper, a professor of climate and space sciences and engineering at the University of Michigan. It was known that closer in, the Sun's magnetic field pulls this wind in the same direction as its rotation, so the team expected this effect would weaken further out. "To our great surprise, as we neared the Sun, we've already detected large rotational flows -- 10 to 20 times greater than what standard models of the Sun predict," Kasper said. "So we are missing something fundamental about the Sun and how the solar wind escapes." Professor Kasper, you are not only missing one fundamental issue about the Sun, but you are missing the most fundamental physics facts about the Sun, including the most fundamental of them all. I have been arguing for so many years that the current model is a DOGMA. These data from Parker Solar Probe are not surprising for me. Not, at all. These data make complete sense. They show the physical reality of the Sun, just like what advanced space telescopes have already shown. For instance, the Solar Dynamic Observatory has provided data that should have been sufficient to throw the standard Solar Model into a trash can. However, if you give me a chance, I can show you these fundamental facts that you are missing about the Sun. I can provide you with a model that solves all the mysteries and puzzles that are associated with current model, including rational explanation to these new data from Parker Solar Probe and future data. Furthermore, and most importantly, my proposed model is the theoretical framework of how to replicate the primary energy source of the Sun.

Post a comment

Your name: *

Your email address: *

Comment text: *

The image that appears on your comment is your Gravatar