Replication data for: Collisionless Magnetic Reconnection in an Asymmetric Oxygen Density Configuration

Particle-in-cell (PIC) simulation for space plasma physics that is used in the article 'Collisionless Magnetic Reconnection in an Asymmetric Oxygen Density Configuration'. Magnetic reconnection is one of the most important energy release and transport processes in plasmas. In case of the Earth's magnetosphere, magnetic reconnection is the primary mechanism responsible for the transport of energy, mass, momentum, and magnetic flux into Earth's magnetic cavity. On the night side, magnetic flux is transported from two inflow regions (north and south) to meet in what is known as the current layer. We simulate a specific scenario where heavy particles, here oxygen, which are asymmetrically distributed accompany the flow of the more abundant plasma species (e.g. protons and electrons) towards the current layer. This simulation is designed to mimic magnetotail reconnection for an asymmetric oxygen density configuration. Oxygen is uniformly distributed above 2.5 proton inertial lengths over the current layer.
Combined with the magnetic field, the distribution of charged particles in the inflow region is expected to control the rate of magnetic reconnection. This paper investigates how the reconnection process is altered by a cold, asymmetrically distributed, oxygen population, which is initially located away from the current layer in the inflow regions. A Particle-In-Cell (PIC) simulation is used to gain further insight into the dynamics of the system. The time evolution of the reconnection process proceeds rapidly compared to the cyclotron period of O^+. It, therefore, remains, to a good approximation, demagnetized. Therefore, Alfvén scaling is not an adequate description of the reconnection rate. A scaling relation for the reconnection rate for an asymmetrically distributed, demagnetized species has been developed. Additionally, we find that an asymmetric density configuration leads to a distinct motion of the reconnection site and generates an asymmetry of the diffusion region and the Hall electric field.

本数据集为用于论文《非对称氧密度构型中的无碰撞磁重联》的空间等离子体物理粒子网格（Particle-in-cell, PIC）模拟数据。磁重联是等离子体中最为重要的能量释放与输运过程之一。就地球磁层而言，磁重联是将能量、质量、动量与磁通量输运至地球磁腔的核心机制。在地球磁尾夜晚侧，磁通量从南北两个流入区域被输送至被称为电流层的区域交汇。本模拟设置了特定场景：以氧为代表的重粒子呈非对称分布，伴随丰度更高的等离子体组分（如质子与电子）向电流层流动。该模拟旨在复现非对称氧密度构型下的磁尾磁重联过程。在电流层上方2.5倍质子惯性长度的区域内，氧粒子呈均匀分布。结合磁场环境，流入区域内带电粒子的分布被认为是调控磁重联速率的关键因素。本研究探讨了初始分布于流入区域且远离电流层的冷态非对称氧粒子群体对磁重联过程的影响机制。本研究采用粒子网格（PIC）模拟以深入解析该系统的动力学行为。相较于氧离子（O⁺）的回旋周期，磁重联过程的时间演化速度极快，因此氧离子在极佳近似下处于退磁化状态。正因如此，阿尔文标度律无法准确描述该场景下的磁重联速率。本研究已推导出适用于非对称分布退磁化组分的磁重联速率标度关系。此外，本研究发现非对称密度构型会使重联位点产生显著位移，并导致扩散区域与霍尔电场呈现非对称分布。