FGM fluxgate magnetometer

Each Cluster spacecraft carries an identical FGM instrument (Fluxgate Magnetometer) to measure the DC magnetic field vector. Each instrument, in turn, consists of two triaxial fluxgate magnetometers and an onboard data processing unit. The instrument samples the magnetic field at a cadence of 22 Hz (67 Hz in Burst mode). In order to minimise the magnetic background of the spacecraft, one of the magnetometer sensors (the outboard, or OB sensor) is located at the end of one of the two 5 m radial booms of the spacecraft, the other (the inboard, or IB sensor) at 1.5 m inboard from the end of the boom. Since the start of the scientific operations on February 1, 2001, only the outboard sensor on each satellite has been used. All FGM datasets are available on the ESA Cluster Science Archive at https://csa.esac.esa.int/

每一颗Cluster卫星均搭载了一台相同的FGM仪器（霍尔效应磁力计），用以测量直流磁场矢量。每台仪器又由两个三轴霍尔效应磁力计以及一台机载数据处理单元组成。该仪器以22赫兹（突发模式下的67赫兹）的采样频率对磁场进行采样。为最小化卫星的磁场背景，其中一台磁力计传感器（外置，或称OB传感器）位于卫星两个5米径向支架的末端之一，而另一台（内置，或称IB传感器）则位于支架末端内侧1.5米处。自2001年2月1日科学操作开始以来，各卫星仅使用外置传感器。所有FGM数据集均可在欧洲空间局Cluster科学档案库中获取，访问链接为https://csa.esac.esa.int/。