Discover the photo voltaic wind with a brand new view of small photo voltaic constructions – Watts with it?
From NASA
January 19, 2021
Scientists have combined NASA data and state-of-the-art image processing to gain new insights into the solar structures that generate the sun’s solar power at high speed. This is detailed in new research published today in the Astrophysical Journal. This first look at relatively small features called “plumelets” could help scientists understand how and why perturbations form in the solar wind.
The magnetic influence of the sun extends for billions of kilometers far beyond the orbit of Pluto and the planets, defined by a driving force: the solar wind. This constant outflow of solar material carries the sun’s magnetic field into space, where it shapes the surroundings around the earth, other worlds, and within the reach of space. Changes in solar wind can create space weather effects that affect not only the planets, but also human and robotic explorers throughout the solar system – and this work suggests that relatively small, previously unexplored features near the sun’s surface could play a crucial role in the properties of the Solar wind.
“This shows the importance of small structures and processes on the sun in understanding the large-scale solar wind and space weather systems,” said Vadim Uritsky, solar scientist at the Catholic University of America and NASA’s Goddard Space Flight Center, who led the study.
Like any solar material, which is made up of a type of ionized gas called plasma, the solar wind is controlled by magnetic forces. And the magnetic forces in the solar atmosphere are particularly complex: The solar surface is traversed by a constantly changing combination of closed magnetic field loops and open magnetic field lines that extend into the solar system.
Scientists used image processing on high-resolution images of the sun to reveal various “plumelets” within structures on the sun called solar plumes. The full disk sun and the left side of the inserted image were recorded by NASA’s Solar Dynamics Observatory in a wavelength of extreme ultraviolet light and processed to reduce the noise. The right side of the inset has been further processed to improve small features in the pictures and to reveal the edges of the plumelets in detail. These plumelets could help scientists understand how and why perturbations occur in the solar wind. Credits: NASA / SDO / Uritsky, et al
The sun’s solar wind escapes into space along these open magnetic field lines. Areas of open magnetic field on the sun can create coronal holes, spots of relatively low density that appear as dark spots in certain ultraviolet views of the sun. Geysers made of solar material are often embedded in these coronal holes, which pour outwards from the sun for days and are known as springs. These solar flags appear bright in extreme ultraviolet views of the sun and are therefore easily visible to observatories such as NASA’s Solar Dynamics Observatory satellite and other spacecraft and instruments. As regions with particularly dense solar material in an open magnetic field, feathers play a major role in generating the rapid solar wind – which means that their properties can influence the properties of the solar wind itself.
Using high-resolution observations from NASA’s Solar Dynamics Observatory (SDO) satellite and an image processing technique developed for this work, Uritsky and coworkers found that these springs are actually made up of much smaller strands of material, which they call plumelets. While the entire cloud in the SDO images extends for approximately 70,000 miles, the width of each plumelet strand is only a few thousand miles in diameter, ranging from approximately 2,300 miles the smallest to approximately 4,500 miles in width for the widest observed plumelets.
Although previous work has indicated a structure within solar plumes, this is the first time scientists have observed plumelets in sharp focus. The techniques used to process the images reduced the “noise” in the sun images and produced a sharper view that revealed the plumelets and their subtle changes in clear detail.
Her work, which focuses on a sun vane observed on July 2nd and 3rd, 2016, shows that the brightness of the cloud comes almost entirely from the individual flags, without much additional blurring between the structures. This suggests that plumelets are more than just a feature within the larger system of a cloud, but rather the building blocks that make up feathers.
“Humans have seen structures in and around the base of springs for some time,” said Judy Karpen, one of the study’s authors and director of the space weather laboratory in NASA Goddard’s heliophysics division. “But we found that the cloud itself is a bundle of those denser, flowing feathers, which is very different from the image of feathers we had before.”
They also found that the plumelets move individually, each oscillating on its own – suggesting that the behavior of these structures on a small scale, in addition to their collective behavior on a large scale, may be a major cause of solar wind disruption.
Search for Plumelet signatures
The processes that create the solar wind often leave signatures in the solar wind itself – changes in the wind’s speed, composition, temperature, and magnetic field that can provide clues as to the underlying physics of the sun. Solar plumelets can also leave such fingerprints and reveal more about their precise role in creating the solar wind, although finding and interpreting these fingerprints can be a complex challenge in its own right.
A key source of data will be NASA’s Parker Solar Probe, which has flown closer to the sun than any other spacecraft and will reach distances of up to 4 million miles from the sun’s surface by the end of its mission. It takes high-resolution measurements of the solar wind, which the sun swings every few months. His observations, closer to the sun and more detailed than those from previous missions, could reveal Plumelet signatures.
Indeed, one of Parker Solar Probe’s early and unexpected findings could be related to plumelets. During its first solar flyby in November 2018, Parker Solar Probe observed sudden reversals in the direction of the magnetic field of the solar wind, known as “serpentines”. The cause and exact nature of the serpentines is still a mystery to scientists, but small-scale structures like plumelets could generate similar signatures.
During its first solar flyby in November 2018, NASA’s Parker Solar Probe observed serpentines – sudden reversals in the solar wind’s magnetic field, as shown here. Newly observed sun plumelets could produce signatures similar to serpentines. Credits: NASA’s Goddard Space Flight Center / Conceptual Image Lab / Adriana Manrique Gutierrez
Finding signatures of the plumelets in the solar wind itself also depends on how well those fingerprints survive their journey away from the Sun – or if they get smeared somewhere along the millions of miles they travel from the Sun to our space observatories .
Assessment of this question will rely on distant observatories like ESA and NASA’s Solar Orbiter, which have already captured the closest solar images, including a detailed view of the sun’s surface – images that only improve as the spaceship approaches the sun. NASA’s upcoming PUNCH mission – led by one of the authors of the Plumelets study, Craig DeForest – will examine how the solar atmosphere transitions to the solar wind and could provide answers to that question as well.
“PUNCH will directly observe how the solar atmosphere changes to the solar wind,” said Uritsky. “This will help us understand if the plumelets can survive if they spread away from the sun – if they can actually be injected into the solar wind.”
By Sarah Frazier
NASA’s Goddard Space Flight Center, Greenbelt, Md. Last updated: January 19, 2021 Publisher: Sarah Frazier
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