A new NASA-funded study has revealed the origins of spicules
– lengthy jets of plasma on the sun’s surface.
Scientists have been observing these long strands of solar material since the end of the 19th century,
but their origins have been difficult to study because they’re highly dynamic and short-lived.
There are roughly 10 million spicules on the surface at any given time.
They can grow up to 6,000 miles long and jet off the sun at 60 miles per second.
Each one appears and collapses over the course of 5 to 10 minutes.
Until recently, what drives these jets has been a mystery.
In a new study, a model more than 10 years in the making was able to simulate spicules for the first time.
Scientists compared the model simulations with observations
from NASA’s Interface Region Imaging Spectrograph, or IRIS,
and the Swedish 1-meter Solar Telescope based in La Palma, Spain.
And found they were closely matched.
With an accurate model of spicules, scientists could explore their origins.
The model reveals that a key component of spicule formation
is the interaction between charged and neutral particles with the magnetic field.
Scientists believe that this interaction drags tangled magnetic field lines up above the sun's surface
allowing them to straighten and expel solar material at high speeds similar to a whiplash.
The model also shows this whiplash process creating strong magnetic waves,
which scientists think could participate in heating the sun’s atmosphere
and propelling the constant outflow of solar material called solar wind.
Understanding spicules helps us to understand one of the ways that energy moves throughout our entire solar system.