It is believed that the heliosphere protects the planets of the solar system from powerful radiation from supernovae and other cosmic rays. Astrophysicists suggest that the heliosphere extends far beyond the solar system. At the same time, no one knows for sure its shape, or even size.
Astrophysicist from the University of Maryland, James Drake, who participated in the study, explains that this "bubble" is quite important for humanity as a whole. The heliosphere generated by the Sun protects us from galactic cosmic rays, and its shape is related to how many and what rays can penetrate inside. The folds, wrinkles and other features of this "protective bubble" affect all this.
Ofer's team has built some of the most advanced computer simulations of the heliosphere to date, using the data and knowledge gathered by astronomers from theoretical astrophysics. The team called the project to predict the shape and features of the heliosphere SHIELD (Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics).
Simulating the heliosphere, scientists are trying to find answers to several questions. What is its structure as a whole? How do its ionized particles behave in time? How does the heliosphere interact with interstellar space, with the matter and radiation existing there? How does it trap or allow cosmic rays?
Astrophysicists describe how external streams of neutral hydrogen particles shape the heliosphere in A Turbulent Heliosheath Driven by the Rayleigh – Taylor Instability, published in the Astrophysical Journal. The paper also describes a hypothesis that explains the reasons for the instability of heliospheric jets - flows of matter and energy, similar to flows arising in other physical processes. For example, some stars and black holes have approximately the same jets.
Judging by the modeling, the heliosphere moving in space with the solar system is not stable. Older models of the heliosphere made it look like a comet with a jet tail. The current model predicts that the heliosphere may look more like something like a croissant or even a donut.
The reason for the instability and irregular shape is precisely the streams of neutral hydrogen particles. Colliding with the heliosphere, they constantly deform it. The model explains for the first time why the shape of the heliosphere "breaks" at the poles, and how galactic cosmic rays hit the Earth and its vicinity.
In particular, this leads to such a phenomenon as the Rayleigh - Taylor instability - when materials with different with a density, the lighter material penetrates the heavier one. Another example of how this phenomenon works is the "fingers" in the famous Horsehead Nebula.
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