MMS 2 Magnetic Ephemeris and Coordinates (MEC) and Support (Tsyganenko 1989 model, Dynamic conditions), Level 2 (L2), Burst Mode, 30 ms Data

Magnetospheric Multiscale 2 (MMS 2) spacecraft position, velocity, attitude, angular momentum vector, and magnetic ephemeris and coordinates (MEC), Level-2 science data at Burst (30 ms) time resolution. The Magnetic ephemeris data are calculated by using the Tsyganenko 1989 magnetic field model for disturbed magnetospheric conditions. Many variables are included in this data product including the magnetic field measured at the spacecraft. If possible, the northern and southern hemisphere footpoints of the spacecraft are found by tracing along the magnetic field line threading through the spacecraft per the given Tsyganenko and internal magnetic field models. The northern and southern hemisphere loss cone angles are also given. The magnetic field strength at the footpoints and the minimum magnetic field strength along the field line are also calculated by using the field models. Other variables list the spacecraft L-shell, the magnetic local time, the magnetic latitude and longitude, and whether the threading field line is open, closed, etc. Rotational quaternions are provided to allow coordinate transformation from GEI into 11 other coordinate systems including BSC, GEO, GSE, GSE2000, GSE, and SM. The list of ancillary variables includes the dipole tilt angle, the Dst and Kp actvity indices, and separate flags that denote satellite eclipse by the Earth and Moon.

磁层多尺度任务2号（MMS 2）航天器的位置、速度、姿态、角动量矢量，以及磁星历与坐标（MEC）数据集，为爆发模式（30毫秒）时间分辨率的二级科学数据。磁星历数据基于适配受扰磁层环境的齐加年科1989（Tsyganenko 1989）磁场模型计算生成。该数据产品涵盖多类变量，其中包含航天器原位测量的磁场数据。若条件允许，将依据给定的齐加年科磁场模型与内部磁场模型，沿贯穿航天器的磁力线进行回溯，以确定航天器所在磁力线的南北半球足点；数据集同时提供南北半球的损失锥角参数。依托上述磁场模型，还可计算得到磁力线足点处的磁场强度，以及整条磁力线的最小磁场强度。其余变量还包括航天器的L壳参数、磁地方时、磁纬度与磁经度，以及贯穿磁力线的开闭状态等信息。数据集提供旋转四元数，可实现从地心赤道惯性坐标系（Geocentric Equatorial Inertial, GEI）到其余11种坐标系的坐标转换，涵盖BSC、GEO、GSE、GSE2000以及SM坐标系。辅助变量列表包含偶极倾角、Dst与Kp地磁活动指数，以及分别标记航天器被地球与月球遮挡的状态标志位。