2023-12-13 11:51:26
MADRID, 13 Dic. (EUROPA PRESS) –
A new plasma instability discovered by scientists in Germany promises to revolutionize our understanding of the origin of cosmic rays and its dynamic impact on galaxies.
At the beginning of the last century, Austrian physicist Victor Hess discovered a new phenomenon called cosmic rays that later earned him the Nobel Prize. He performed high-altitude balloon flights to discover that the Earth’s atmosphere is not ionized by radioactivity in the ground. Instead, he confirmed that the origin of the ionization was extraterrestrial. It was later determined that cosmic “rays” consist of charged particles from outer space flying at close to the speed of light rather than radiation. However, the name “cosmic rays” survived these findings.
In the new study, Dr. Mohamad Shalaby, from the Leibniz Institute for Astrophysics Potsdam (AIP) and lead author of this study, and his collaborators have carried out Numerical simulations to follow the trajectories of many cosmic ray particles and study how they interact with the surrounding plasma, made up of electrons and protons. The paper appears on the arXiv preprint server.
When the researchers studied the cosmic rays flying back and forth across the simulation, they discovered a new phenomenon that excites electromagnetic waves in the background plasma. These waves exert a force on the cosmic rays, which changes their sinuous paths.
Most importantly, this new phenomenon can be better understood if we consider that cosmic rays do not act as individual particles but support a collective electromagnetic wave. When this wave interacts with the fundamental waves in the background, These are strongly amplified and an energy transfer occurs.
“This idea allows us to consider that cosmic rays behave in this context as radiation and not as individual particles, as Victor Hess initially believed,” comments it’s a statement Professor Christoph Pfrommer, head of the Cosmology and High Energy Astrophysics section of the AIP. A good analogy for this behavior is that individual water molecules collectively form a wave that breaks on the shore.
“This progress only occurred considering smaller scales that until now had been overlooked and that question the use of effective hydrodynamic theories in the study of plasma processes“explains Dr. Mohamad Shalaby.
There are many applications of this newly discovered plasma instability, including a first explanation of how electrons from thermal interstellar plasma can be accelerated to high energies in supernova remnants.
“This newly discovered plasma instability represents a significant advance in our understanding of the acceleration process and finally explains why these supernova remnants glow in radio and gamma rays,” reports Mohamad Shalaby. Furthermore, this groundbreaking discovery opens the door to a deeper understanding of the fundamental processes of cosmic ray transport in galaxies, representing the greatest mystery in our understanding of the processes that shape galaxies during their cosmic evolution.
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