Abstract
Three-dimensional (3D) simulations of electron beams propagating in high-energy-density plasmas using the quasistatic Particle-in-Cell (PIC) code QuickPIC demonstrate a significant increase in stopping power when beam electrons mutually interact via their wakes. Each beam electron excites a plasma wave wake of wavelength , where is the speed of light and is the background plasma frequency. We show that a discrete collection of electrons undergoes a beam-plasma-like instability caused by mutual particle-wake interactions that causes electrons to bunch in the beam, even for beam densities for which fluid theory breaks down. This bunching enhances the beam's stopping power, which we call “correlated stopping,” and the effect increases with the “correlation number” . For example, a beam of monoenergetic 9.7 MeV electrons with , in a cold background plasma with (450 g DT), has a stopping power of times the single-electron value, which increases to for . The beam also experiences transverse filamentation, which eventually limits the stopping enhancement.
1 More- Received 21 October 2019
- Revised 30 January 2021
- Accepted 21 July 2021
DOI:https://doi.org/10.1103/PhysRevE.104.035203
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