CAPER-2 Flew Through Northern Lights to Catch Waves

The Cusp Alfven and Plasma Electrodynamics Rocket-2 (CAPER-2) flew through active Aurora Borealis to study the waves, which accelerate electrons into our atmosphere.

The CAPER-2 mission was launched on 4^th January 2019 from the Andoya Space Center in Andenes. A 4-stage Black Brant XII sounding rocket was used for this purpose, which climbed to an apogee of 480 miles before crashing into the Arctic Sea. The flight through the Northern Lights allowed the researchers of the mission to study the acceleration of particles in space. Scientists at NASA believe that a closer inspection of this amazing phenomenon (Aurora) can provide us with some useful insights about the atmospheres throughout the solar system and beyond. In addition to that, it can also prove incredibly useful for protecting our technology in space. Jim LaBelle, the Principal Investigator for the CAPER-2 mission who works as a Space Physicist at Dartmouth College, referred to that by saying,

“Throughout the universe, you have charged particles getting accelerated — in the Sun’s atmosphere, in the solar wind, in the atmospheres of other planets, and in astrophysical objects. An aurora presents us with a local laboratory where we can observe these acceleration processes close at hand.”

CAPER-2, a Sounding Rocket

A sounding rocket is an instrument-carrying rocket that can perform scientific experiments and take measurements during its flight. These rockets are used on short, targeted trips to space. They fall back to Earth immediately after completing the assigned task. They are probably the most suitable option for exploring transient events (Northern Lights) because of their quick development time and low price tags.

Primary Objective of the CAPER-2 Mission

Electrons, surging towards our atmosphere from space, smash into the atmospheric gases to produce the glow which results in this magnificent aurora. The basic aim of the researching team is to determine the events happening just before an aurora starts glowing. Observations have revealed that the pace of these negatively-charged particles increases significantly as they enter the atmosphere of Earth. Doug Rowland, a Space Physicist at the Goddard Space Flight Center of NASA, also agreed that these electrons are traveling at least 10 times faster (when they enter our atmosphere) than they were before. Despite this information, scientists haven’t been able to figure out the scientific reason for this acceleration.

The primary focus of the researchers of the CAPER-2 was on a special kind of daytime aurora because we hardly know anything about them. The fact that this aurora is triggered directly by the electrons coming from the Sun adds to its worth for research purposes. Craig Kletzing, the Co-investigator for the mission who is a Space Physicist at the University of Iowa, talked about the significance of studying this aurora and said,

“There’s been a huge amount of research done on the regular nighttime aurora, but the daytime aurora is much less studied. There are good indications that there are some similarities and there are also some differences.”

Influence of Waves on Daytime Auroras

The mission revolves around the idea of determining the impact of waves on the electrons that create daytime auroras. Scientists are most concerned about 2 types of waves, having opposite effects. The first one of them is known as ‘Langmuir Waves’. Electrons generate them on their own and transfer some of the energy to these waves in order to slow down. On the other hand, the waves that are considered the reason behind the acceleration of electrons are called ‘Alfven Waves’. They propagate along the magnetic field of Earth and can stretch up to hundreds of miles from peak to peak. These massive waves are named after Hannes Alfven, a Swedish Scientist, who discovered them for the first time.

The CAPER-2 mission will help researchers to measure these waves as it carries a high-resolution wave-particle correlator. The researching team had to travel to Norway for this mission because it is one of those places that can put a rocket within range of the daytime aurora. Basically, northern Norway rotates under the ‘Northern Polar Cusp’, an opening in the magnetic field of the Earth where particles from the Sun can funnel into our upper atmosphere. This makes it an ideal place to observe and understand these physical processes. LaBelle mentioned that in the following words:

“It’s a kind of natural laboratory. We take our experiment to two different environments, where the variables are different, and then test the theory and answer the questions.”