Nanoscale Electrostatic Modulation of Mega-Ampere Electron Current in Solid-Density Plasmas

• Published in: Physical review letters Vol. 127; no. 24; p. 245002
• Main Authors: Li, R, Huang, T W, Ju, L B, Yu, M Y, Zhang, H, Wu, S Z, Zhuo, H B, Zhou, C T, Ruan, S C
• Format: Journal Article
• Language: English
• Published: United States 10-12-2021
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.127.245002

Transport of high-current relativistic electron beams in dense plasmas is of interest in many areas of research. However, so far the mechanism of such beam-plasma interaction is still not well understood due to the appearance of small time- and space-scale effects. Here we identify a new regime of electron beam transport in solid-density plasma, where kinetic effects that develop on small time and space scales play a dominant role. Our three-dimensional particle-in-cell simulations show that in this regime the electron beam can evolve into layered short microelectron bunches when collisions are relatively weak. The phenomenon is attributed to a secondary instability, on the space- and timescales of the electron skin depth (tens of nanometers) and few femtoseconds of strong electrostatic modulation of the microelectron current filaments formed by Weibel-like instability of the original electron beam. Analytical analysis on the amplitude, scale length, and excitation condition of the self-generated electrostatic fields is clearly validated by the simulations.