An aurora is seen over Greenland on April 2, 2011. Two NASA sounding rockets
will launch into a particular type of aurora called a cusp aurora this winter to study
different processes related to the particle acceleration that causes cusp auroras.
The cusp is a region near the North Pole where Earth’s magnetic field is directly
connected to the solar wind, allowing daytime auroras to form.
Credits: NASA/University of Maryland, College Park/Robert Michell
(November 25, 2015) This winter, two sounding rockets will launch through the aurora borealis over Norway to study how particles move in a region near the North Pole where Earth’s magnetic field is directly connected to the solar wind. After the launch window opens on Nov. 27, 2015, the CAPER and RENU 2 rockets will have to wait for low winds and a daytime aurora before they can send their instrument payloads soaring through the Northern Lights.
Both instrument packages are studying phenomena related to the cusp aurora, a particular subset of the Northern Lights in which energetic particles are accelerated downward into the atmosphere directly from the solar wind – that is, the constant outward flow of solar material from the sun. Though cusp auroras are not particularly rare, they are often difficult to spot because they only happen during the day, when sunlight usually drowns out what would otherwise be a spectacular light show. However, because the magnetic North Pole is offset from the geographic North Pole, it’s often possible to see cusp auroras in Northern Europe near the winter solstice.
Part of CAPER, short for Cusp Alfven and Plasma Electrodynamics Rocket, is suspended
from the rail that will carry the rocket out to the launch pad. CAPER’s launch window will
open Nov. 27, 2015, and scientists will have to wait for good weather conditions and a daytime
cusp aurora before they can send their payload flying through the aurora borealis.
CAPER will study the electromagnetic waves that both create the cusp aurora and send
electrons flying out into space. Credits: NASA/Nate Empson
“The magnetic pole is tilted towards North America, putting this magnetic opening—the cusp—at a higher latitude on the European side,” said Jim LaBelle, principal investigator on the CAPER sounding rocket at Dartmouth College in Hanover, New Hampshire. “Combine that extra-high latitude with the winter solstice—when nights are longest, especially as you go farther north—and you can sometimes see this daytime aurora with the naked eye.”
The two sounding rocket teams will also employ data from ground-based radars to detect the cusp aurora even in the case of clouds.