Scientists for the first time have observed elusive oscillations in the Sun's corona, known as Alfvén waves, that transport energy outward from the surface of the Sun. The discovery is expected to give researchers more insight into the fundamental behavior of solar magnetic fields, eventually leading to a fuller understanding of how the Sun affects Earth and the solar system.
The research, led by Steve Tomczyk of the National Center for Atmospheric Research (NCAR), is being published this week in Science.
"Alfvén waves can provide us with a window into processes that are fundamental to the workings of the Sun and its impacts on Earth," says Tomczyk, a scientist with NCAR's High Altitude Observatory.
Alfvén waves are fast-moving perturbations that emanate outward from the Sun along magnetic field lines, transporting energy. Although they have been detected in the heliosphere outside the Sun, they have never before been viewed within the corona, which is the outer layer of the Sun's atmosphere. Alfvén waves are difficult to detect partly because, unlike other waves, they do not lead to large-intensity fluctuations in the corona. In addition, their velocity shifts are small and not easily spotted.
"Our observations allowed us to unambiguously identify these oscillations as Alfvén waves," says coauthor Scott McIntosh of the Southwest Research Institute in Boulder. "The waves are visible all the time and they occur all over the corona, which was initially surprising to us."
Insights into the Sun
By tracking the speed and direction of the waves, researchers will be able to infer basic properties of the solar atmosphere, such as the density and direction of magnetic fields. The waves may provide answers to questions that have puzzled physicists for generations, such as why the Sun's corona is hundreds of times hotter than its surface.
The research also can help scientists better predict solar storms that spew thousands of tons of magnetized matter into space, sometimes causing geomagnetic storms on Earth that disrupt sensitive telecommunications and power systems. By learning more about solar disruptions, scientists may be able to better protect astronauts from potentially dangerous levels of radiation in space.
"If we want to go to the moon and Mars, people need to know what's going to happen on the Sun," Tomczyk says.
A powerful instrument
To observe the waves, Tomczyk and his coauthors turned to an instrument developed at NCAR over the last few years. The coronal multichannel polarimeter, or CoMP, uses a telescope at the National Solar Observatory in Sacramento Peak, New Mexico, to gather and analyze light from the corona, which is much dimmer than the Sun itself. It tracks magnetic activity around the entire edge of the Sun and collects data with unusual speed, making a measurement as frequently as every 15 seconds.
The instrument enabled the research team to simultaneously capture intensity, velocity, and polarization images of the solar corona. Those images revealed propagating oscillations that moved in trajectories aligned with magnetic fields, and traveled as fast as nearly 2,500 miles per second.
David Hosansky | EurekAlert!
A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University
A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences