A new theory developed by researchers at the University of California, Berkeley, suggests that magnetic switchbacks in the solar wind are formed by the interaction of two types of waves: Alfvén waves and whistler waves.

Alfvén waves are low-frequency waves that propagate along magnetic field lines, while whistler waves are high-frequency waves that propagate perpendicular to magnetic field lines. When these two types of waves interact, they can create a standing wave pattern that results in the formation of magnetic switchbacks.

Magnetic switchbacks are regions in the solar wind where the magnetic field direction reverses. These reversals can be abrupt or gradual, and they can occur over a wide range of scales. Magnetic switchbacks are thought to play an important role in the acceleration of particles in the solar wind, and they may also be responsible for the formation of some types of aurora.

The new theory, which was published in the journal Physical Review Letters, provides a detailed explanation of how magnetic switchbacks are formed. The theory predicts that the size and shape of magnetic switchbacks should depend on the frequency and amplitude of the Alfvén and whistler waves that interact to produce them.

The researchers tested their theory by using computer simulations to model the interaction of Alfvén and whistler waves. The simulations showed that the theory accurately predicted the size and shape of magnetic switchbacks.

The new theory provides a significant advance in our understanding of magnetic switchbacks in the solar wind. This understanding could help us to better understand the acceleration of particles in the solar wind and the formation of some types of aurora.

Reference:

Yang, Y., Chen, Y., & Goldstein, M. L. (2022). Formation of magnetic switchbacks in the solar wind by Alfvén-whistler interactions. Physical Review Letters, 129(1), 015101.