[ad_1]
In order to better observe the sun and study the solar wind, a team of researchers has created its own miniature sun in the laboratory, with its own electromagnetic field and ultra-powerful plasma.
Scientists at the University of Wisconsin-Madison built the 3-meter-wide (10-foot) aluminum vacuum chamber, which they dubbed "the big red ball," to recreate some of the solar physics that take place in and around the sun.
"I was attracted to [the experiment’s] Ethan Peterson, a graduate student in the university's physics department and lead author of the study, told Space.com.
Related: Anatomy of storms and solar flares (computer graphics)
The solar model had a magnet at its center to mimic the sun magnetic field, and researchers would pump helium inside the small sun to ionize the gas and turn it into plasma. They would then apply an electric current that, along with the magnetic field, would turn the plasma.
The sun and its atmosphere consist of plasma, a mixture of positively and negatively charged particles at extremely high temperatures. Solar wind transports this plasma in a stream away from the sun and in space.
"We also know that the sun is a spinning plasma ball, so we make a plasma in this dipolar magnetic field, rotate it and see what happens," Peterson said.
Peterson, with his physics professor Cary Forest, began by reproducing the "Parker spiral" – named after Eugene Parker, the astrophysicist behind the solar wind theory. Parker's spiral refers to the spiral shape that the sun's magnetic field forms above the solar surface while being driven by the solar wind.
The mini-sun had a magnetic field embedded in its nucleus.
(Image credit: UW-Madison)
"[Our] The effort was to … confirm or disprove the theoretical derivation for the solar wind and the heliospheric magnetic field that Parker discovered in 1958, "Peterson said.
Indeed, the Parker spiral took shape.
During the experiment, the researchers also observed plasma drops ejected by the solar wind. "We were first surprised to observe these plasmoids, or plasma blobs, ejected at such a steady frequency," Peterson said.
The so-called "plasma rounds" were similar to plasma ejections of the true sun that have been observed by the satellites. The source of these real ejections remains unknown. Observing their mini-sun, the researchers mapped a region where the magnetic field was weaker and the plasma was moving faster, causing the material to rupture and radiate out.
According to Peterson, the "Big Red Ball" created its first plasma in 2012, and researchers have been upgrading it since then, as it goes through a cycle of experiments.
The team will use the mini-sun to study in more detail how the solar wind is accelerated away from the sun, as well as the fundamental properties of collisionless plasmas.
The results were published on July 29 in the journal Physical Nature.
Follow Passant Rabie on Twitter @passantrabie. follow us on Twitter @Spacedotcom and on Facebook.
[ad_2]
Source link
