Supercomputer simulation of plasma electron heat conductivity decrease due to relativistic electron beam relaxation

A 3D kinetic study of the relaxation processes caused by the propagation of an electron beam in high-temperature plasma was carried out. This problem has two dierent spatial scales: the plasma Debye length and the beam-plasma interaction wavelength, that is some 10 or 100 times larger, thus one needs high-performance computing to observe the two lengths at once. The mathematical model is built on the basis of the Particle-in-Cell (PIC) method. The algorithm was parallelized by means of the mixed Lagrange-Eulerian domain decomposition. The parallelization eciency is presented as well as the performance of the program achieved with four dierent clusters. The performance tests show that it is necessary to provide a good memory bandwidth for the cluster if one wants to achieve good performance on real physical problems. It is shown that the emergence of regions with small electron energy flow observed in computations is connected with the decrease of electron heat conductivity. Beam relaxation leads to electron heat conductivity decrease by two or three orders of magnitude.