How do relativistic electrons form at shocks?

What is it about?

We have developed a new model showing that shock waves in space can naturally boost electrons to very high energies. These shock waves occur in many environments, such as around supernovas, stars, and planets. By combining satellite measurements with modern theories, we found that electrons starting with only modest energy can be rapidly accelerated when they interact with waves in space. This process happens under normal solar wind conditions, especially when the wind is fast, and does not need any special triggers. The discovery helps explain puzzling observations of high-energy electrons near Earth and offers new insight into the origins of cosmic rays. The model is based on fundamental plasma processes and could apply to many different cosmic environments.

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Photo by Aldebaran S on Unsplash

Photo by Aldebaran S on Unsplash

Why is it important?

The physical processes that accelerate the electrons are fundamental and occur throughout the Universe making our model applicable to other planets in our solar system and even to exoplanets around distant stars. In these exotic environments, the unique conditions could allow electrons to reach even higher energies than what we observe near Earth. By studying our own space environment, we proposed a framework of electron acceleration that addresses the long-lasting and persistent question of "How can energetic (relativistic) electrons form at planetary collisionless shocks?". Apart from addressing this fundamental question, our work also addresses practical concerns related to space weather, as energetic electrons can significantly impact satellite operations, communication systems, and power grids at Earth.

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