New Understanding of Betatron Oscillations Paves Way for Long-distance and High-energy Plasma-based Particle Accelerators

Chinese researchers have discovered the general rules of betatron oscillations applicable to long-distance plasma-based particle accelerators. 
In a theoretical work recently accepted by Physical Review Accelerators and Beams, Prof.ZENG Ming's plasma acceleration theory group has established a three-dimensional model and derived equations for the long-term behavior of betatron oscillations.
The plasma-based accelerator is one of the most promising candidates for future high-energy particle accelerators and colliders, thanks to its extremely high acceleration gradient. This feature may substantially reduce the total size of such machines, thus making it possible for accelerators to achieve higher energy levels than ever before. Until now, development of long-distance plasma-based accelerators has been hampered by a limited understanding of particle behavior. 
The researchers have discovered new phenomena based on this model, such as the precession of betatron oscillations in the betatron phase shift dominant regime (a), the polarization linearization in the radiation reaction dominant regime (b), and so on. This model will be key to designing future plasma-based high-energy accelerators and colliders.
(a) In the betatron phase shift dominant regime, the particle trajectory gradually rotates about the origin, which indicates precession movement of the elliptical betatron oscillations.
(b) In the radiation reaction dominant regime, the ellipse becomes thinner, which indicates that a generally elliptical polarization approaches linear polarization.
Fig. Evolution of the particle trajectory (red ellipse) in the x-y plane (perpendicular to the acceleration direction). The blue arrows indicate the rotation direction of the particle. (Image by IHEP)

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