Science Current Events | Science News | Brightsurf.com
 

Warm coronal loops offer clue to mysteriously hot solar atmosphere

May 30, 2008
Scientists at NASA reveal a new understanding of the mysterious mechanism responsible for heating the outer part of the solar atmosphere, the corona, to million degree temperatures.

"It has become clear in recent years that coronal heating is a highly dynamic process, but inconsistencies between observations and theoretical models have been a major source of heartburn. We have now discovered two possible solutions to this dilemma: energy is released impulsively with the right mix of particle acceleration and direct heating, or energy is released gradually very close to the solar surface," says James Klimchuk, an astrophysicist at the Goddard Space Flight Center's Solar Physics Laboratory in Greenbelt, Md. Klimchuk will present his team's findings on May 29 at the American Geophysical Union conference in Ft. Lauderdale, Fl.

X-rays and ultraviolet radiation from the solar corona affect Earth and its atmosphere. For satellites, this can be a real drag-literally. As Earth's atmosphere gets hotter, it expands and becomes denser at high altitudes. When this happens, satellites experience more drag, which changes their orbits. Accurately predicting this "space weather" gives satellite operators more time to respond to or avert problems that could potentially cause interruptions and outages.

In order for scientists to build realistic models of the corona, they "must understand coronal heating. It's the root cause of all this radiation," says Klimchuk.

A comparison of numerical simulations with imaging and spectral data from NASA missions reveals that the coronal heating mechanism is highly impulsive, or concentrated close to the solar surface, or both.

The corona is made up of loops of hot gas that arch high above the sun's surface. These loops can have a wide range of temperatures, many reaching several million degrees Kelvin, but those of intermediate temperature have proven the most difficult to explain. Impulsive energy bursts called nanoflares seem to be the key. "Nanoflares can release their energy in different ways, including the acceleration of particles, and we now understand that the right mix of particle acceleration and direct heating is one way to explain the observations," says Klimchuk.

Another possibility is that energy release happens very gradually, but very close to the sun's surface. In this case, a phenomenon called thermal nonequilibrium causes the loops to go through periodic fits of dynamic behavior. The latest computer simulations suggest that these solar temper tantrums may also be able to explain the observations.

Either way, accurate space weather forecasts rely on a good physical understanding of how the corona works. How the corona radiates depends entirely on its thermal structure, and its thermal structure depends entirely on its heating. Detailed studies of nanoflare heating and thermal nonequilibrium are taking scientists one step closer to understanding the Sun-Earth connection.

NASA/Goddard Space Flight Center


Related Solar Atmosphere Current Events and Solar Atmosphere News Articles


Bright Points in Sun's Atmosphere Mark Patterns Deep In Its Interior
Like a balloon bobbing along in the air while tied to a child's hand, a tracer has been found in the sun's atmosphere to help track the flow of material coursing underneath the sun's surface.

NASA Releases Images of X-class Solar Flare
The sun emitted a significant solar flare, peaking at 1:48 p.m. EDT March 29, 2014, and NASA's Solar Dynamics Observatory captured images of the event.

Astronomers find solar storms behave like supernovae
Researchers at UCL have studied the behaviour of the Sun's coronal mass ejections, explaining for the first time the details of how these huge eruptions behave as they fall back onto the Sun's surface.

SOHO Shows New Images of Comet ISON
As Comet ISON heads toward its closest approach to the sun - known as perihelion - on Nov. 28, 2013, scientists have been watching through many observatories to see if the comet has already broken up under the intense heat and gravitational forces of the sun.

NASA's Solar Observing Fleet to Watch Comet ISON's Journey around the Sun
It began in the Oort cloud, almost a light year away. It has traveled for over a million years. It has almost reached the star that has pulled it steadily forward for so long. On Thanksgiving Day, Nov. 28, 2013, Comet ISON will finally sling shot around the sun.

A close look at the Toby Jug Nebula
Located about 1200 light-years from Earth in the southern constellation of Carina (The Ship's Keel), the Toby Jug Nebula, more formally known as IC 2220, is an example of a reflection nebula.

New and remarkable details of the sun now available from NJIT's Big Bear Observatory
Researchers at NJIT's Big Bear Solar Observatory (BBSO) in Big Bear, CA have obtained new and remarkably detailed photos of the Sun with the New Solar Telescope (NST).

Solar tsunami used to measure Sun's magnetic field
A solar tsunami observed by NASA's Solar Dynamics Observatory (SDO) and the Japanese Hinode spacecraft has been used to provide the first accurate estimates of the Sun's magnetic field.

Space Instrument Adds Big Piece to the Solar Corona Puzzle
The Sun's visible surface, or photosphere, is 10,000 degrees Fahrenheit. As you move outward from it, you pass through a tenuous layer of hot, ionized gas or plasma called the corona.

NASA's IRIS Spacecraft Is Fully Integrated
NASA's next Small Explorer (SMEX) mission to study the little-understood lower levels of the sun's atmosphere has been fully integrated and final testing is underway.
More Solar Atmosphere Current Events and Solar Atmosphere News Articles

Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment (Space Science Series)

Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment (Space Science Series)
by Steven W. Bougher (Editor), Donald M. Hunten (Editor), Roger J. Phillips (Editor)


The final orbit of Venus by the Magellan spacecraft in October 1994 brought to a close an exciting period of Venus reconnaissance and exploration. The scientific studies resulting from data collected by the Magellan, Galileo, and Pioneer missions are unprecedented in their detail for any planet except Earth. Venus II re-evaluates initial assessments of Venus in light of these and other spacecraft missions and ground-based observations conducted over the past 30 years. More than a hundred contributors summarize our current knowledge of the planet, consider points of disagreement in interpretation, and identify priorities for future research. Topics addressed include geology, surface processes, volcanism, tectonism, impact cratering, geodynamics, upper and lower atmospheres, and...

Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System (Astronomy and Astrophysics Library)

Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System (Astronomy and Astrophysics Library)
by Eugene F. Milone (Author), William J.F. Wilson (Author)


The second edition of Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System provides a timely update of our knowledge of planetary atmospheres and of the bodies of the outer solar system and their analogs in other planetary systems. This volume begins with an expanded treatment of the physics, chemistry, and meteorology of the atmospheres of the Earth, Venus, and Mars, moving on to their magnetospheres and then to a full discussion of the gas and ice giants and their properties. From here, attention switches to the small bodies of the solar system, beginning with the natural satellites. The comets, meteors, meteorites, and asteroids are discussed in order, and the volume concludes with the origin and evolution of our solar system. Finally, a fully revised section on...

Ultraviolet and X-ray Spectroscopy of the Solar Atmosphere (Cambridge Astrophysics)

Ultraviolet and X-ray Spectroscopy of the Solar Atmosphere (Cambridge Astrophysics)
by Kenneth J. H. Phillips (Author), Uri Feldman (Author), Enrico Landi (Author)


The solar atmosphere, above the Sun's surface layers, reaches mega-kelvin temperatures and high levels of dynamic activity through processes involving a pervading magnetic field. This 2008 book explores one of the principal means of understanding the solar atmosphere, its ultraviolet and soft X-ray emission. The ultraviolet and X-ray spectra of the Sun's atmosphere provide valuable information about its nature - the heat and density of its various parts, its dynamics, and chemical composition. The principles governing spectral line and continuous emission, and how spectral studies lead to deductions about physical properties, are described, together with spacecraft instrumentation from Skylab, SolarMax, Yohkoh, SOHO, TRACE, and Hinode. With introductions to atomic physics and diagnostic...

The Solar System

The Solar System
by Michael A. Seeds (Author), Dana Backman (Author)


With this newly revised Eigth Edition of THE SOLAR SYSTEM, the authors' goals are to help you use astronomy to understand science--and use science to understand what we are. Fascinating, engaging, and visually vibrant, this text will help you answer two fundamental questions: What are we? And how do we know?

Solar System: A Visual Exploration of All the Planets, Moons and Other Heavenly Bodies that Orbit Our Sun

Solar System: A Visual Exploration of All the Planets, Moons and Other Heavenly Bodies that Orbit Our Sun
by Marcus Chown (Author)


Based on the latest ebook sensation developed by Theodore Gray and his company Touch Press, this beautiful print book presents a new and fascinating way to experience the wonders of the solar system

Following the stunning success of both the print edition and the app of The Elements, Black Dog & Leventhal and Touch Press have teamed up again. Solar System is something completely new under the sun. Never before have the wonders of our solar system—all its planets, dwarf planets, the sun, moons, rocky Asteroid Belt, and icy Kuiper Belt—been so immediately accessible to readers of all ages.

Beginning with a fascinating overview and then organized by planet, in order of its distance from the sun, Solar System takes us on a trip across time and space that includes a...

Solar Energy Fundamentals and Modeling Techniques: Atmosphere, Environment, Climate Change and Renewable Energy

Solar Energy Fundamentals and Modeling Techniques: Atmosphere, Environment, Climate Change and Renewable Energy
by Zekai Sen (Author)


This book presents the methods of quantitative determination of solar irradiation incident amount on a surface on the Earth. It brings together information not found elsewhere in a single source, and includes an innovative exposition of expert system methodologies used in the domain of solar irradiation and energy. The book provides a background to the underlying physical principles of solar irradiation and energy, with explanations as to how these can be modelled and applied.

  Physics of the Sun: Volume II: The Solar Atmosphere (Geophysics and Astrophysics Monographs)
by P.A. Sturrock (Editor)




Build Your Own Solar Panel: Generate Electricity from the Sun.

Build Your Own Solar Panel: Generate Electricity from the Sun.
by Phillip Hurley (Author)


Whether you're trying to get off the grid, or you just like to experiment, Build Your Own Solar Panel has all the information you need to build your own photovoltaic panel to generate electricity from the sun. Now available for the first time in print, this revised and expanded edition has easy-to-follow directions, and over 150 detailed photos and illustrations. Lists of materials, tools, and suppliers of PV cells are included. Every-day tools are all that you need to complete these projects.
Build Your Own Solar Panel will show you how to:
Design and build PV panels,
Customize panel output,
Make tab and bus ribbon,
Solder cell connections,
Wire a photovoltaic panel,
Purchase solar cells,
Test and rate PV cells,
Repair damaged solar cells,
Work...

Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System (Astronomy and Astrophysics Library) (v. 2)

Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System (Astronomy and Astrophysics Library) (v. 2)
by Eugene F. Milone (Author), William J.F. Wilson (Author)


The book covers the field of solar system astrophysics beginning with basic tools of spherical astronomy and coordinate frames and celestial mechanics. It therefore presents equations and derivations starting from a level that permits one to see the underlying physical ideas. An up-to-date overview on all essential topics is presented, but is concise where possible. The text is based on extensive experience in the classroom and its contents have been field-tested by students for years. The material has been updated in the last few months to take advantage of the newer discoveries of the Mars Rover and the Saturn Cassini missions.

Solar Electricity Basics: A Green Energy Guide

Solar Electricity Basics: A Green Energy Guide
by Dan Chiras (Author)


The future will be powered by renewables. As we transition away from finite and polluting fossil fuels, clean, reliable, and affordable renewable technologies such as solar electricity will become the mainstay of our energy supply.  Solar Electricity Basics provides a clear understanding of electricity and energy. It discusses the types of solar electric system you can choose from, their components, solar site assessment, the installation of photovoltaic systems, and much more. Whether your goal is to lower your energy bill or to achieve complete energy independence, Solar Electricity Basics is the introduction you need. Dan Chiras is a respected educator and an internationally acclaimed author who has published more than twenty-five books on residential renewable energy and green...

© 2014 BrightSurf.com