Our sun erupts regularly, spewing huge flames of heat, and to better understand how it works, researchers have created a version that fits in your lunchbox.
Using a device that converts powerful bursts of electricity into filamentous rings of plasma, a team of physicists have simulated solar flares to study the powerful X-rays and energetic particles passing through the solar system.
A team led by physicist Yang Zhang of the California Institute of Technology wrote: “Observations of the Sun detect energetic particles and hard X-rays, but fail to reveal the generation mechanism because particle acceleration occurs at a scale smaller than the resolution of the observation. Here we present observations from a laboratory experiment. which mimics the physics of coronal rings.
And the Sun is a very dynamic ball of plasma powered by nuclear fusion, so it’s no wonder it’s capable of a few tricks. Powerful explosions, throwing light and particles into the surrounding space, can affect the solar system over long distances.
And we certainly experience these effects here on Earth. The magnetosphere and atmosphere protect us from hard, high-energy X-rays, but solar emissions can interfere with satellites and spacecraft, including navigation and communications technology, and cause power grid fluctuations and disruptions. So scientists, of course, want to know more about how the sun creates and emits material in the first place.
But we can learn a lot by looking at the sun itself. There is a limit to the number of observations we can make with today’s technology. To study these finer details, physicists turned to the next best way: reproducing solar flares in the lab.
Physicist Paul Bellan of the California Institute of Technology has developed an experimental device specifically to create structures known as coronal rings. These are long, closed arcs of luminous plasma emitted by the solar photosphere along magnetic field lines that protrude into the solar corona. They are often associated with increased solar activity such as flares and coronal mass ejections.
This device consists of gas nozzles, electromagnets and electrodes in a vacuum chamber.
First, electromagnets are triggered, creating a magnetic field inside the vacuum chamber. The gas is then injected into the electrode area.
A strong electrical discharge on a millisecond scale is then applied to the electrodes; This ionizes the gas, turning it into plasma, which then forms a ring bound by a magnetic field.
“Each experiment consumes about the same amount of energy as turning on a 100-watt light bulb for about a minute, and it only takes a few minutes to charge a capacitor,” Bilan explains.
Each ring lasts only 10 microseconds and is very small, about 20 centimeters (7.9 inches) long and one centimeter in diameter. But high-speed cameras capture every moment of the ring’s formation and propagation, allowing the research team to analyze its formation, structure and evolution in detail.
Scientists have recently learned that coronal loops not only look like threads, but are also arranged in such a way. The new work allowed the team to see what role this structure plays in the production of solar projectiles.
It turns out that these filaments are responsible for X-ray flashes. Because the plasma is a strong conductor, current flows through the loops; But from time to time the current exceeds the capacity of the circuit, like water flowing through a hose.
When this happens, as the team’s images show, a corkscrew-like instability develops in the ring, and individual strands begin to break, putting more stress on the remaining strands.
When the filament breaks, a burst of X-rays is produced, followed by a surge of negative voltage. This voltage drop causes the charged particles in the plasma to accelerate; As these particles slow down, they emit a burst of X-rays.
Future research on the Sun will help unravel this process, but it appears to be consistent with other research that has found how cutting and reconnecting magnetic field lines results in powerful bursts of energy. The team plans to explore different ways coronal rings combine and reconfigure to see what types of explosions this activity produces.
The study is published in the journal Nature Astronomy.
Source: Science Alert
You must log in to post a comment.