Simulation study of coupled two-stream and current filamentation instability excited by accelerator electron beams in plasmas

Abstract

A gas-discharge plasma device is simulated with COMSOL software, and the obtained plasma density profile is input into a two-dimensional particle-in-cell code, in which the transport of relativistic electron beams in the plasma with an actual density profile is investigated. The results show that the device can produce a wide range of high-density plasmas with the maximum density approaching [Formula: see text] m−3. With the relativistic electron beams produced from a linear electron accelerator, the gas-discharge plasma is shown to be an ideal medium for the investigation of coupled two-stream and current filamentation instability.

Ion effects on the scaling of magnetic field amplification in plasmas with the system size

“…The scaling of the magnetic field amplification with the system size for the case of movable ions is also confirmed with three-dimensional (3D) PIC simulations, using the code EPOCH [39] directions. Different from the transverse 2D simulations, the system is initially dominated by the oblique two-stream instability [28,36] (i.e. the coupled two-stream and CFI) in the 3D simulations, as the chevron-shaped pattern imprinted on the beam density profile shown in figure 9(a).…”

“…Time evolutions of the transverse magnetic field energy E B ⊥ and beam electron energy E be are shown in figure 2 for the two plasma cases. The growth rate of the instability is [12,28,36,37], where β = v be0 /c, α is the beam-to-plasma density ratio, as indicated in figure 2(a). Good agreement is found between the theory and simulation results.…”