The Solar Orbiter has detected a “pipe” of cooler atmospheric gases that is rapidly making its way through the Sun’s strong magnetic field. This observation provides an exciting new addition to the zoo of features revealed by the Solar Orbiter mission, led by the European Space Agency (ESA). It is particularly interesting because the snake was the precursor to a much larger explosion. The snake was spotted on September 5, 2022, as the Solar Orbiter spacecraft approached the Sun for a close pass on October 12. The “snake” is a tube of cold plasma suspended by magnetic fields in the warmer surrounding plasma of the Sun’s atmosphere. Plasma is a state of matter very similar to the more familiar solids, liquids and gases. The plasmas are so incredibly hot that the electrons leave their atoms, making it essentially a gas of charged particles. As charged particles, they are therefore sensitive to magnetic fields. All the gases in the Sun’s atmosphere are plasma because the temperature there is over a million degrees Celsius. The plasma in the snake follows a particularly long filament of the Sun’s magnetic field that reaches from one side of the Sun to the other. ESA’s Solar Orbiter mission will face the Sun through the orbit of Mercury on its closest approach. Credit: ESA/ATG medialab “You get the plasma flowing from one side to the other, but the magnetic field is actually twisted. So you get this change in direction because we’re looking down at a twisted structure,” says David Long, Mullard Space Science Laboratory (UCL), UK, who is leading research into the phenomenon. The movie at the top of this page is made as a time-lapse from images from the Extreme-Ultraviolet Imager (EUI( onboard Solar Orbiter. In fact, the snake took about three hours to complete its journey. However, at the distances that involved in crossing the solar surface, this means the creature must have been traveling at about 170 kilometers per second (106 miles per second), or 612,000 km per hour (380,000 miles per hour). What makes the snake so interesting is that it started from a solar active region that later exploded, spewing billions of tons of plasma into space. This raises the possibility that the snake was some kind of precursor to this event – and the Solar Orbiter caught it all on multiple instruments. The Extreme-Ultraviolet Imager (EUI) is a suite of remote-sensing telescopes that can image the structures in the solar atmosphere from the chromosphere to the corona in high resolution. The instrument package includes two high-resolution telescopes and a full sun imaging system. Credit: Max Planck Institute For the spacecraft’s Energetic Particle Detector (EPD), the burst was one of the most intense solar energetic particle events detected so far by the instrument. “It’s a really nice combination of data sets that we only get from Solar Orbiter,” says David. Even more interestingly, the plasma from this explosion, known as a coronal mass ejection, happened to sweep NASA’s Parker Solar Probe, allowing its instruments to measure the contents of the explosion. Being able to see an explosion take place and then sample the ejected gases, either with its own instruments or those of another spacecraft, is one of Solar Orbiter’s main science goals. It will allow a better understanding of solar activity and how it creates “space weather,” which can disrupt satellites and other technology on Earth. The Solar Orbiter is an international collaboration space mission between ESA and NASA, operated by ESA. It launched on February 9, 2020 and celebrated its 1000th day in space earlier this month.
