Electron beams and radio signals from the surface of the Sun

Nov 15, 2013
The STEREO spacecraft and the sun. Credit: NASA

The sun emits light, but it also emits particle beams. A scientist at the Swedish Insitute of Space Physics (IRF) in Uppsala has revealed how these beams generate radio waves. These radio waves can tell us about the outer layers of the sun and the interstellar medium without going there. In particular, the radio emissions are produced in small packages, and their shapes are determined by the density changes in the solar wind.

"We have known for a long time that the sun can produce electromagnetic emissions at the same frequencies as ordinary radio stations on Earth. If we can understand how these are produced they could be used to probe the outer layers of the sun and , without going there, just by observing the natural radio signals," says Daniel Graham, an Australian scientist now working at IRF. The results are presented in the important physics journal Physical Review Letters.

The NASA Solar TErrestrial RElations Observatory (STEREO) mission, launched in 2006, consists of two spacecraft which orbit the sun, one ahead of Earth and the other behind Earth. These spacecraft have better instruments than previous satellites for observing waves.

Electron beams emitted from the sun are the start of a multi-stage process generating these radio waves. The electron beams travel out into the and generate a type of wave that cannot travel very far (electrostatic Langmuir waves). These waves can then generate natural radio waves, and these can be seen at Earth.

"This might provide us with information about the outer layers of the sun and the solar wind," says Daniel Graham, "but only if we understand all steps producing these radio signals."

Daniel Graham has used observations by STEREO where Langmuir waves were naturally converted into radio waves. These data might help us understand how information was transferred from the outer layers of the , to the electron beam, then into Langmuir waves, which are converted to and eventually reach Earth. This has to be done in space, since only the radio signals (as opposed to the Langmuir waves) can reach the surface of the Earth.

Explore further: Venus Express spacecraft, low on fuel, does delicate dance above doom below

More information: D. B. Graham and Iver H. Cairns, Constraints on the Formation and Structure of Langmuir Eigenmodes in the Solar Wind, Physical Review Letters, vol. 111, issue 12 (2013): prl.aps.org/abstract/PRL/v111/i12/e121101

add to favorites email to friend print save as pdf

Related Stories

NASA's SDO sees sun emit a mid-level solar flare

Oct 24, 2013

The sun emitted a mid-level solar flare that peaked at 8:30 pm EDT on Oct. 23, 2013. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to ...

Heating the solar wind

Apr 03, 2013

(Phys.org) —The Sun glows with a surface temperature of about 5500 degrees Celsius. Meanwhile its hot outer layer (the corona) has a temperature of over a million degrees, and ejects a wind of charged particles ...

Radio waves carry news of climate change

Jul 30, 2013

The ionosphere, one of the regions of the upper atmosphere, plays an important role in global communications. Ionized by solar radiation, this electricity-rich region is used for the transmission of long ...

Another M-class flare from Sunspot 1515

Jul 05, 2012

Active Region 1515 has now spit out 12 M-class flares since July 3. Early in the morning of July 5, 2012 there was an M6.1 flare. It peaked at 7:44 AM EDT. This caused a moderate – classified as R2 on ...

Sun emits third solar flare in two days

Oct 28, 2013

UPDATE: Another solar flare erupted from the same area of the sun on Oct. 25, 2013,which peaked at 11:03 a.m. EDT. This flare is classified as an X2.1 class.

Recommended for you

Orion on track at T MINUS 1 Week to first blastoff

17 hours ago

At T MINUS 1 Week on this Thanksgiving Holiday, all launch processing events remain on track for the first blast off of NASA's new Orion crew vehicle on Dec. 4, 2014 which marks the first step on the long ...

Bad weather delays Japan asteroid probe lift off

Nov 28, 2014

Bad weather will delay the launch of a Japanese space probe on a six-year mission to mine a distant asteroid, just weeks after a European spacecraft's historic landing on a comet captivated the world.

Manchester scientists boost NASA's missions to Mars

Nov 27, 2014

Computer Scientists from The University of Manchester have boosted NASA space missions by pioneering a global project to develop programs that efficiently test and control NASA spacecraft.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1 / 5 (11) Nov 16, 2013
"This might provide us with information about the outer layers of the sun and the solar wind," says Daniel Graham, "but only if we understand all steps producing these radio signals."


Only if....

"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory." Hannes Alfven
Protoplasmix
1 / 5 (10) Nov 16, 2013
If we can understand how these radio emissions are produced they could be used to probe the outer layers of the sun and interstellar medium, without going there, just by observing the natural radio signals

Well spotted, good eye :)
---
All the sky's a lab
And the men and women are surveyors
And scientists and seekers of the how's, what, why's, when, where's
Every life is lived
In a thousand different ways
With abundance in their grasp and sunshine in their days
Conundrums all get solved
And the paradoxes vanish
The future did arrive as ignorance was banished
Posterity is free
From being born in debt
Since a better way was found there's never been regret
Science is the tool
Its method is the way
Imagination is required and the rest is merely play.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.