Pseudo-Maxwellian Velocity Distribution Formed by the Pickup-like Process in Magnetic Reconnection

Focusing on ring-shaped ion velocity distributions with a finite width formed in magnetic reconnection the presence of guide field, intriguing properties such as formation mechanism, significant change shape, and necessary conditions for are investigated by means theory simulations. The ring distribution predominantly originates from variations seed particles pickup-like process. A function exactly representing is analytically formulated, assuming steady supply satisfying Maxwellian mixing gyration phases. formulated indicates that when larger than criterion, local minimum ring’s center changed into maximum, shape transformed mountain shape. Such mountain-like defined “a pseudo-Maxwellian distribution,” because it almost indistinguishable genuine distribution. Actually, particle simulations demonstrate mountain-shaped during nearly concluded they distributions. Moreover, two types evidence shown One to analyze dependence which explored simulation. In cases slightly different values vague shapes rings observed other observe under hypothetical condition an artificial zero temperature upstream utilizing test simulation, clearly seen, reduced. From evidence, definitely confirmed found These results imply would be created various field reconnection.