Tendrils of plasma near the surface of the sun emerge from realignments of magnetic fields and pump heat into the corona, the sun’s tenuous outer atmosphere, a study suggests.
The new observation, described in the Nov. 15 Science, could help crack the century-plus mystery of where these plasma whiskers, called spicules, come from and what role — if any — they play in heating the corona to millions of degrees Celsius.
Spicules undulate like a wind-whipped field of wheat in the chromosphere, the layer of hot gas atop the sun’s surface. These plasma filaments stretch for thousands of kilometers and last for just minutes, shuttling ionized gas into the corona. Astronomers have long debated how spicules form — with the sun’s turbulent magnetic field being a prime suspect — and whether they can help explain why the corona is a few hundred times as hot as the sun’s surface (SN: 8/20/17).
To look for connections between spicules and magnetic activity, solar physicist Tanmoy Samanta of Peking University in Beijing and colleagues pointed the Goode Solar Telescope, at Big Bear Solar Observatory in California, at the sun. They snapped images of spicules forming, while also measuring the surrounding magnetic field. The team discovered that thickets of spicules frequently emerged within minutes after pockets of the local magnetic field reversed course and pointed in the opposite direction from the prevailing field in the area.