NASA Records Song of Earth’s Magnetic Field

A NASA spacecraft has recorded the song of the Earth's magnetic field.

The song called as chorus is actually electromagnetic phenomenon that is caused by plasma waves in Earth's radiation belts called the Van Allen radiation belts using an Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) receiver to record the signals. 

The instrument built by a team at the University of Iowa is part of the NASA's twin Radiation Belt Storm Probes (RBSP) designed for a mission to explore the Earth's radiation belts in near-Earth space. The radiation belts are surrounded by charged particles and the mission is to understand the effect of solar storm and coronal mass ejections from the sun on the radiation belts.  

The two spacecraft, which were launched in August 2012, was the first twin-probe mission that have identical orbits and cover the entire radiation belt region around the Earth.  

It will measure the interaction between the charged plasma waves that produce energetic ions and relativistic electrons. At times, these electrons gain energy by catching a chorus wave and cause trouble to satellites and astronauts, according to NASA.

The radiation belts produce oscillating radio waves called chorus that range between 0 and 10 kHz frequencies. The waves detected are believed to energize the electrons that form the outer radiation belt.

While ham radio operators have recorded the songs, the signals recorded by EMFISIS are clear. Moreover, the data recorded is of 16 bits and is of high quality.

"This is what the radiation belts would sound like to a human being if we had radio antennas for ears," researcher Craig Kletzing, of the University of Iowa, said in a statement.

"One of things we noticed right away is how clear the chorus sounds in the recording. That's because our data is sampled at 16 bits, the same as a CD, which has not been done before in the radiation belts. This makes the data very high quality and shows that our instrument is very, very healthy," he said.

Kletzing hopes to do stereo recordings of Earth's chorus so as to figure out the broad region over which chorus occurs.