Magnetometer

The magnetometers on Vega 1 and Vega 2 were
designed to measure the magnetic field and its low-frequency fluctuations in the
cometary and solar wind interaction zone and in interplanetary space. The
instrument on each spacecraft consisted of two fluxgate sensor units (one axial
and triaxial) mounted 1 m apart on a 2-m boom. The advantage of this dual-sensor fluxgate system is the possibility to determine the spacecraft's stray magnetic field.

The axial unit was oriented along the spacecraft symmetry (X) axis, which was
perpendicular to the solar panels and pointed toward the Sun. Each sensor had a
dynamic range of ± 100 nT, sensitivity of 0.05 nT (12 bit) and a noise level of 0.01 nT/Hz^(1/2). Magnetic field vectors were measured with a sampling frequency of 10 vectors per second.

The magnetometers operated in three data rate modes:

* 1) the measured components were averaged during 2.5 minutes and transmitted to telemetry;
* 2) the measured components were averaged during 1 minute and transmitted to telemetry;
* 3) direct transmission mode, the measured components were transmitted to telemetry without averaging.

Cruise phase data were mostly taken in the 2.5-min averaging mode.

Vega 1号和Vega 2号上的磁力仪旨在测量彗星与太阳风相互作用区域以及星际空间中的磁场及其低频波动。每艘航天器上的仪器由两个霍尔效应传感器单元（一个轴向和三轴向）组成，这些单元被安装在2米长的支架上，相距1米。这种双传感器霍尔效应系统的优势在于能够确定航天器的杂散磁场。轴向单元沿航天器对称轴（X轴）方向布置，该轴与太阳能电池板垂直，并指向太阳。每个传感器具有±100纳特（nT）的动态范围，0.05纳特（nT）的灵敏度（12位），以及0.01纳特/赫兹^(1/2)的噪声水平。磁场矢量以每秒10矢量的采样频率进行测量。磁力仪在三种数据速率模式下运行：1）测量分量在2.5分钟内平均，并传输至遥测系统；2）测量分量在1分钟内平均，并传输至遥测系统；3）直接传输模式，测量分量不经平均直接传输至遥测系统。巡航阶段的数据主要采用2.5分钟平均模式采集。