Numerical and experimental investigation of fusion relevant two-stream instability

Summary form only given. During the transit of an electron beam through a background plasma, instabilities can occur that may result in highly dynamic behaviour. This behaviour may be important in fast-ignition inertial confinement fusion. In one method of this type of fusion, a deuterium-tritium pellet is compressed by lasers to very high densities. An ignition laser pulse then interacts with a directional gold cone to produce a highly relativistic electron beam that streams into the compressed pellet. This beam-plasma interaction can result in the two-stream instability. The dynamics associated with this instability is investigated in this work. It has been proposed that this instability can resonantly decay into ion-acoustic waves which can then be damped by the ion collisions to dissipate the beam energy, heating the fusion fuel^1,2. To investigate this behaviour, computational simulations have been undertaken in the two-dimensional particle-in-cell (PiC) code XOOPIC. These simulations have investigated a lower energy, low density regime where a 50kV, 24A, rectilinear electron beam is injected into a waveguide bounded, magnetically confined, cylindrical plasma column of a density of 1.8×10¹⁶m⁻³. Using the parameters from this simulation, a low temperature, low density laboratory experiment is currently being designed to provide an experimental benchmark for the results predicted by the code. This will provide an enhanced confidence in the use of PiC and other numerical methods to predict the dynamics of fusion relevant conditions.