. 24/7 Space News .
SOLAR SCIENCE
Solving the Sun's Super-Heating Mystery with Parker Solar Probe
by Staff Writers
Ann Arbor MI (SPX) Jun 06, 2019

In this "zone of preferential heating" above the Sun's surface, temperatures rise overall. More bizarre still, individual elements are heated to different temperatures, or preferentially. Some heavier ions are superheated until they're 10 times hotter than the hydrogen that is everywhere in this area - hotter than the core of the Sun.

It's one of the greatest and longest-running mysteries surrounding, quite literally, our Sun - why is its outer atmosphere hotter than its fiery surface? University of Michigan researchers believe they have the answer, and hope to prove it with help from NASA's Parker Solar Probe.

In roughly two years, the probe will be the first man-made craft to enter the zone surrounding the Sun where heating looks fundamentally different that what has previously been seen in space. This will allow them to test their theory that the heating is due to small magnetic waves traveling back and forth within the zone.

Solving the riddle would allow scientists to better understand and predict solar weather, which can pose serious threats to Earth's power grid. And step one is determining where the heating of the Sun's outer atmosphere begins and ends - a puzzle with no shortage of theories.

"Whatever the physics is behind this superheating, it's a puzzle that has been staring us in the eye for 500 years," said Justin Kasper, a U-M professor of climate and space sciences and a principal investigator for the Parker mission. "In just two more years, Parker Solar Probe will finally reveal the answer."

The U-M theory, and how the team will use Parker to test it, is laid out in a paper published June 4 in The Astrophysical Journal Letters.

In this "zone of preferential heating" above the Sun's surface, temperatures rise overall. More bizarre still, individual elements are heated to different temperatures, or preferentially. Some heavier ions are superheated until they're 10 times hotter than the hydrogen that is everywhere in this area - hotter than the core of the Sun.

Such high temperatures cause the solar atmosphere to swell to many times the diameter of the Sun and they're the reason we see the extended corona during solar eclipses. In that sense, Kasper says, the coronal heating mystery has been visible to astronomers for more than a half millennium, even if the high temperatures were only appreciated within the last century.

This same zone features hydromagnetic "Alfven waves" moving back and forth between its outermost edge and the Sun's surface. At the outermost edge, called the Alfven point, the solar wind moves faster than the Alfven speed, and the waves can no longer travel back to the Sun.

"When you're below the Alfven point, you're in this soup of waves," Kasper said. "Charged particles are deflected and accelerated by waves coming from all directions."

In trying to estimate how far from the Sun's surface this preferential heating stops, U-M's team examined decades of observations of the solar wind by NASA's Wind spacecraft.

They looked at how much of helium's increased temperature close to the Sun was washed out by collisions between ions in the solar wind as they traveled out to Earth. Watching the helium temperature decay allowed them to measure the distance to the outer edge of the zone.

"We take all of the data and treat it as a stopwatch to figure out how much time had elapsed since the wind was superheated," Kasper said. "Since I know how fast that wind is moving, I can convert the information to a distance."

Those calculations put the outer edge of the superheating zone roughly 10 to 50 solar radii from the surface. It was impossible to be more definitive since some values could only be guessed at.

Initially, Kasper didn't think to compare his estimate of the zone's location with the Alfven point, but he wanted to know if there was a physically meaningful location in space that produced the outer boundary.

After reading that the Alfven point and other surfaces have been observed to expand and contract with solar activity, Kasper and co-author Kristopher Klein, a former U-M postdoc and new faculty at University of Arizona, reworked their analysis looking at year-to-year changes rather than considering the entire Wind mission.

"To my shock, the outer boundary of the zone of preferential heating and the Alfven point moved in lockstep in a totally predictable fashion despite being completely independent calculations," Kasper said. "You overplot them, and they're doing the exact same thing over time."

So does the Alfven point mark the outer edge of the heating zone? And what exactly is changing under the Alfven point that superheats heavy ions? We should know in the next couple of years. The Parker Solar Probe lifted off in August 2018 and had its first rendezvous with the Sun in November 2018 - already getting closer to the Sun than any other human-made object.

In the coming years, Parker will get even closer with each pass until the probe falls below the Alfven point. In their paper, Kasper and Klein predict it should enter the zone of preferential heating in 2021 as the boundary expands with increasing solar activity. Then NASA will have information direct from the source to answer all manner of long-standing questions.

"With Parker Solar Probe we will be able to definitively determine through local measurements what processes lead to the acceleration of the solar wind and the preferential heating of certain elements," Klein said. "The predictions in this paper suggest that these processes are operating below the Alfven surface, a region close to the Sun that no spacecraft has visited, meaning that these preferential heating processes have never before been directly measured."

Kasper is the principal investigator of the Solar Wind Electrons Alphas and Protons investigation on the Parker Solar Probe. SWEAP's sensors scoop up the solar wind and coronal particles during each encounter to measure velocity, temperature and density, and shed light on the heating mystery.

Research Report: "Strong Preferential Ion Heating Is Limited to Within the Solar Alfven Surface," Justin C. Kasper and Kristopher G. Klein, 2019 June 4, Astrophysical Journal Letters


Related Links
Parker Solar Probe
Solar Science News at SpaceDaily


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


SOLAR SCIENCE
The sun follows the rhythm of the planets
Dresden, Germany (SPX) May 30, 2019
One of the big questions in solar physics is why the Sun's activity follows a regular cycle of 11 years. Researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), an independent German research institute, now present new findings, indicating that the tidal forces of Venus, Earth and Jupiter influence the solar magnetic field, thus governing the solar cycle. In principle, it is not unusual for the magnetic activity of a star like the Sun to undergo cyclic oscillation. And yet past models ha ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

SOLAR SCIENCE
Russian cosmonauts remove a towel that spent 10 years on surface of ISS

IAF ties up with ISRO for manned mission crew selection

Cosmonauts complete spacewalk at International Space Station

NASA Navigation Tech Shows Timing Really Is Everything

SOLAR SCIENCE
Proton launches Russian comsat Yamal-601 into Orbit

China conducts first sea-based space rocket launch

NASA Makes Progress Assembling Massive Space Launch System Rocket Stage

NASA Reaches New Milestone on Complex, Large Rocket

SOLAR SCIENCE
A European mission control for the Martian rover

The radiation showstopper for Mars exploration

Mars on Earth - what next?

NASA's Mars 2020 gets HD eyes

SOLAR SCIENCE
Yaogan-33 launch fails in north China, Possible debris recovered in Laos

China develops new-generation rockets for upcoming missions

China's satellite navigation industry sees rapid development

China's Yuanwang-7 departs for space monitoring missions

SOLAR SCIENCE
Study Input Informs NASA Course for a Vibrant Future Commercial Space Economy

NewSpace could eliminate Sun-Synchronous orbits

ISRO sets up space tech incubation centre at NITT

Russian space sector plagued by astronomical corruption

SOLAR SCIENCE
US says to take action to ensure rare earths supply

Accurate probing of magnetism with light

High flex, high-energy textile lithium battery aims to meet demand for wearable electronics

China steps up threat to deprive US of rare earths

SOLAR SCIENCE
Pair of Fledgling Planets Seen Growing Around Young Star

ExoMars orbiter prepares for Rosalind Franklin

The 'forbidden' planet has been found in the 'Neptunian Desert'

Bacteria's protein quality control agent offers insight into origins of life

SOLAR SCIENCE
On Pluto the Winter is approaching, and the atmosphere is vanishing into frost

Neptune's moon Triton fosters rare icy union

Juno Finds Changes in Jupiter's Magnetic Field

Gas insulation could be protecting an ocean inside Pluto









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.