Physicists confirm effective wave growth theory in space
Whistler-mode wave magnetic field (blue arrows with spiral) propagating along the magnetic field (purple) interacting with electrons (red) passing through it. Credit: University of Tokyo

For the first time, a team from Nagoya University has observed the transfer of energy from electrons to waves. The non- linear growth theory of waves predicts efficient growth. Our understanding of space weather, a phenomenon that affects satellites, should be improved thanks to this.

People think of outer space as a vacuum. This is not the case because the vacuum is filled with particles. The density of charged particles is so low that they rarely collide.

The motion of charged particles can be controlled by the forces of the electric and magnetic fields. Most of the time, there is no collision between stars, moons, or planets. The charged particles are no longer traveling through the air but through a medium where they can hit other particles.

Some of the charged particles scatter and accelerate in the Earth's atmosphere. Observers see the results of an interaction between waves and electrons when there is a diffuse aurora. Scientists should be able to predict variations in the intensity of highly energetic particles if they study the interactions between themagnetic fields and the particles. The most severe effects of space weather may be protected by this.

A team consisting of Designated Assistant Professor Naritoshi Kitamura and Professor Yoshizumi Miyoshi of the Institute for Space and Earth Science (ISEE) at Nagoya University, as well as researchers from the University of Tokyo, Kyoto University, Tohoku University, Osaka University, and Japan's

The interactions between electrons and whistler-mode waves were studied. By applying a method of using a wave particle interaction analyzer, they were able to detect the ongoing energy transfer from the electrons to the whistler-mode waves. They were able to derive the growth rate of the wave. They published their results in a journal.

The most important finding was that the results were in line with the hypothesis of non- linear growth. This is the first time anyone has directly observed the efficient growth of waves in space for the wave-particle interaction between electrons and whistler-mode waves.

The results are expected to contribute to research on various wave-particle interactions and to improve our understanding of plasma physics research. The results will contribute to our understanding of the effects of the radiation belt on satellites and the loss of high-energy electrons in the atmosphere.

Nature Communications has more information about direct observations of energy transfer from electrons to waves in the Earth's atmosphere. There is a DOI of 10.1038/s41467-022-3.

Journal information: Nature Communications