Resolving extended space and time correlations in molecular dynamics simulations of strongly magnetized plasmas

Strongly magnetized plasmas are characterized by having a gyrofrequency larger than the plasma frequency. In this regime, the motion of charged particles is constrained to small cylinders with a width characterized by the gyroradius and a length characterized by the collision mean free path. Recent molecular dynamics simulations showed that this channeling effect leads to increased temporal and spatial correlations associated with Coulomb collisions [1]. These simulations used cubic domains, which significantly limited the range of magnetization strength that they could explore because it required a large number of particles to resolve the long-range correlations. Here, we show that an elongated domain in the direction of the magnetic field can capture the effects with significantly fewer particles than a cubic domain. We define a unit cubic domain by the size needed to capture weakly magnetized plasmas, then elongate the domain by adding additional cubes in the direction parallel to the magnetic field. A proof of principle is demonstrated by computing the self-diffusion tensor of the strongly magnetized one-component plasma using the velocity autocorrelation function. [1] Vidal, Baalrud, Phys. Plasmas 28, 042103 (2021).