An international team of scientists, including three researchers from the New Jersey Institute of Technology (NJIT), shed new light on one of the central mysteries of solar physics: how the sun's energy is carried into the star's upper atmosphere, heating up to 1 million degrees Fahrenheit and higher in some regions, temperatures that are significantly hotter than the sun's surface.
With new images from the NJIT Big Bear Solar Observatory (BBSO), researchers have discovered in an innovative, detailed way what appears to be a probable mechanism – jets of magnetized plasma known as spicules, which spray like geysers from the upper atmosphere of the sun in a crown.
In a document published today (November 15, 2019) in the journal Science the team describes key features of a jet spiral cups that are in the solar perspective small plasma structures between 200 and 500 kilometers wide, that erupt continuously in the space of the sun. The researchers also show for the first time where and how the jets and roads they travel are generated at speeds of about 100 kilometers per second in some cases to the crown.
"Unprecedented high-resolution observations from BBSO & # 39; s Goode Solar Telescope make it clear that when magnetic fields with opposite polarities reconnect into the lower atmosphere of the Sun, these plasma jets are emitted strongly," says the solar physicist Wenda Khao, BBSO Director and author of the document.
He added: "This is the first time we have seen direct evidence of how spicules are generated. We tracked these dynamic characteristics in the H-alpha spectral line to their feet, measured the magnetic fields at their point, recorded the migration of the emerging magnetic elements, and checked their interaction with existing magnetic fields with opposite polarity. "
Images captured in extreme ultraviolet (EUV) spectra from NASA's Solar Dynamics Observatory spacecraft were used to track the transport of energy into the corona. These observations showed that it is also common for spikes to heat up to typical coronal temperatures.
Invisible to the human eye, except when it turns out to be a brief fiery halo of plasma during a solar eclipse, the crown remains a puzzle even for scientists who study it closely. Starting at 1,300 miles from the star's surface and extending millions more in each direction, it is more than a hundred times hotter than the lower layers much closer to the thermonuclear reactor at the core of the Sun.
Solving what astrophysicists call one of the biggest challenges in solar modeling – identifying the physical mechanisms that heat the upper atmosphere – requires high-resolution images that were not available until the 1.6-meter telescope BBSO, the largest working solar telescope in the world, did not begin imaging a decade ago.
Big Bear scientists (below) also captured the first high-resolution images, for example, of magnetic fields and plasma fluxes occurring deep below the Sun's surface, tracking the evolution of sunspots and ropes of magnetic flux through the chromosphere their appearance in the crown as burning contours.
Khao says that it takes an international team of diverse expertise and equipment, located on Earth and in space, to delve deeper into the fundamental physics of the Sun Cao developed the scientific instruments of the Big Bear telescope and oversaw their work while Vasil NJIT's Yurchishin generates observations, processes data and recommends their use, and NJIT's Kwangsun Ann processes vector magnetic field data for scientific use. Tanmo Samantha and Hui Tian of Beijing University in China identified the novel's findings and wrote the manuscript; they are its first authors.
Scientists from the Max Planck Institute for Solar System Research in Germany, NASA Marshall Space Center, University of Sheffield in the United Kingdom, Eötvös University in Hungary, Kunming University of China, University of Kunming Austria and the Indian Institute of Astrophysics play roles.
Reference: Generation of solar spicules and subsequent heating in the atmosphere by Tanmo Samantha, Hui Tian, Vasil Yurchishin, Hardy Peter, Wenda Khao, Alfonso Sterling, Robertus Erdélyi, Kwangsu Ahn, Song Feng, Dominar Ut and Banik Utar Yajie Chen, November 15, 2019, Science .
doi: 10.1126 / science.aaw2796