” I have actually spent my whole career studying coronal loops,” stated NCAR scientist Anna Malanushenko, who led the study. The filings orient themselves along magnetic field lines that loop from one pole of the bar magnet to the other. The coronal loops seen on the Sun have actually never ever acted precisely as they should, based on our understanding of magnets. If this taken place, the plasma caught in between the field lines would likewise spread out between the limits, creating thicker, less bright loops. The possibility that these loops are instead wrinkles in a coronal veil helps explain this and other disparities with our expectations of the loops– but it likewise asks new questions.
Evident coronal loops observed by NASAs Transition Region And Coronal Explorer (TRACE) spacecraft. Credit: NASA/TRACE
New study challenges long-held presumptions about the structure of the Suns environment.
Numerous coronal loops– ropey hairs of plasma that scientists have long thought existed in the Suns atmosphere– might actually be visual fallacies, according to a new paper that challenges dominating assumptions of what we understand, and dont understand, about the Sun.
The research study, led by the National Center for Atmospheric Research (NCAR) and published in The Astrophysical Journal, depended on a cutting-edge, practical 3D simulation of the solar corona. The simulation, carried out at NCAR a number of years back, enabled the scientists to slice the corona in unique areas in an effort to separate individual coronal loops..
What they discovered is that a lot of the loops werent loops at all.
While the research study group was able to identify a few of the coronal loops they were searching for, they also found that oftentimes what appear to be loops in images taken of the Sun may in fact be wrinkles of intense plasma in the solar environment. As sheets of brilliant plasma fold over themselves, the folds appear like bright thin lines, imitating the look of self-contained and unique strands of plasma..
The findings, which the research team is calling the “coronal veil” hypothesis, have significant implications for our understanding of the Sun, because the assumed coronal loops have been used for years as a way to presume information about density, temperature, and other physical qualities of the solar atmosphere..
” I have spent my whole profession studying coronal loops,” stated NCAR scientist Anna Malanushenko, who led the research study. “I was thrilled that this simulation would provide me the opportunity to study them in more detail. I never expected this. My mind blew up when I saw the results. This is a totally brand-new paradigm of understanding the Suns atmosphere.”.
The research study was funded by NASA and included collaborators from NCARs High Altitude Observatory, Lockheed Martin Solar and Astrophysics Laboratory, the Southwest Research Institute, and NASA Goddard. NCAR is sponsored by the National Science Foundation..
Challenging intuition.
What seems coronal loops can be seen in images taken of the Sun in extreme ultraviolet light. Because it fits our many standard understanding of magnetism, the assumption that they exist is a natural one for researchers.
The majority of schoolchildren have at some point seen what occurs when iron filings are sprinkled near a bar magnet. The filings orient themselves along electromagnetic field lines that loop from one pole of the bar magnet to the other. These curving lines expanded, becoming weaker and less thick, the additional they are from the magnet.
The evident coronal loops in pictures of the Sun appearance strikingly comparable, and because there is a substantial electromagnetic field in the Sun, the existence of electromagnetic field lines that could trap a rope of plasma in between them and develop loops appears like an obvious description. And in fact, the brand-new study confirms that such loops likely exist.
The coronal loops seen on the Sun have actually never ever acted exactly as they should, based on our understanding of magnets. If this happened, the plasma trapped between the field lines would likewise spread out in between the boundaries, creating thicker, less intense loops.
The possibility that these loops are rather wrinkles in a coronal veil assists describe this and other discrepancies with our expectations of the loops– however it also asks new concerns. For instance, what figures out the shape and thickness of the folds? And how numerous of the apparent loops in pictures of the Sun are really genuine hairs, and the number of are optical illusions?.
” This study reminds us as scientists that we need to constantly question our assumptions and that sometimes our instinct can work versus us,” Malanushenko said..
Innovative model offers brand-new view of the Sun.
The discovery that coronal loops might be illusions was made possible thanks to MURaM, a radiative magnetohydrodynamic model that was extended to model the solar corona in an effort led by NCAR. Numerous years ago, a group of scientists led by Lockheed Martin Solar and Astrophysics Laboratory utilized MURaM to develop a very detailed simulation of the solar corona.
The simulation was groundbreaking when it was first produced because it had the ability to concurrently model what was happening in multiple areas of the Sun, from the upper part of the convective zone– about 10,000 kilometers listed below the Suns surface area– through the solar surface area and beyond, as much as almost 40,000 kilometers into the solar corona. These varied areas of the Sun cover a vast variety of physical conditions, consisting of distinctions in density and pressure, therefore researchers had not previously found out a way to mathematically represent these areas in an unified simulation.
Amongst other results, the brand-new simulation had the ability to catch the entire life process of a solar flare for the very first time, from the develop of energy below the solar surface area to the development of flare at the surface area, and finally to the explosive release of energy.
This makes it challenging to inform whether a “loop” that is overlapping other loops is in front or behind. Its also hard to inform whether the loop itself has a compact cross section, like a garden tube, or looks like a long ribbon viewed edge on.
The cubes of data produced by MURaM provide scientists the chance to dissect the solar atmosphere and study the overlapping structures separately, something that is not possible with the instruments and observatories we presently have..
While the MURaM simulation is among the most practical ever produced of the solar corona, its still simply a model. Understanding the number of coronal loops are actually visual fallacies will need carefully developed observational techniques that penetrate the corona and new information analysis strategies.
” We know that creating such methods would be incredibly difficult, however this research study shows that the method we presently interpret the observations of the Sun may not be appropriate for us to really comprehend the physics of our star,” Malanushenko stated..
Referral: “The Coronal Veil” by A. Malanushenko, M. C. M. Cheung, C. E. DeForest, J. A. Klimchuk and M. Rempel, 2 March 2022, The Astrophysical Journal.DOI: 10.3847/ 1538-4357/ ac3df9.