DOI: 10.48322/f8hm-sb42
title: Voyager 1 1-hr Averaged  Triaxial Fluxgate Magnetometer (MAG) Interplanetary Magnetic Field in ASCII Format

description: 
      This data set contains hour averages of the interplanetary magnetic     
      field (IMF) measurements obtained by the triaxial fluxgate magnetometer 
      experiment on Voyager 1. Identical instruments on Voyager 1 and 2 were  
      designed to measure the IMF between  Earth and Saturn (10 AU) during the
      primary Voyager mission. The  design and performance yielded absolute   
      accuracies to better than < 0.1 nT. In general, each component of the   
      hourly average has an uncertainty of up  to (+/- 0.05 nT) in the region 
      beyond 10 AU. More accurate measurements can be  obtained by special    
      processing of the data, but it was not feasible to do this for the      
      entire data set included here. The magnetic field magnitude in nT is    
      provided along with angles of the field vector in the spacecraft-       
      centered Heliographic (HG) coordinate system, also known as RTN.        
                                                                              
    Coordinate System                                                         
    =================                                                         
                                                                              
      Interplanetary magnetic field studies make use of two important         
      coordinate systems, the Inertial Heliographic (IHG) coordinate system   
      and the Heliographic (HG) coordinate system.                            
                                                                              
      The IHG coordinate system is use to define the spacecraft's position.   
      The IHG system is defined with its origin at the Sun.  There are three  
      orthogonal axes, X(IHG), Y(IHG), and Z(IHG).  The Z(IHG) axis points    
      northward along the Sun's spin axis.  The X(IHG) - Y(IHG) plane lays in 
      the solar equatorial plane.  The intersection of the solar equatorial   
      plane with the ecliptic plane defines a line, the longitude of the      
      ascending node, which is taken to be the X(IHG) axis.  The X(IHG) axis  
      drifts slowly with time, approximately one degree per 72 years.         
                                                                              
      Magnetic field orientation is defined in relation to the spacecraft.    
      Drawing a line from the Sun's center (IHG origin) to the spacecraft     
      defines the X axis of the HG coordinate system.  The HG coordinate      
      system is defined with its origin centered at the spacecraft.  Three    
      orthogonal axes are defined, X(HG), Y(HG), and Z(HG).  The X(HG) axis   
      points radially away from the Sun and the Y(HG) axis is parallel to the 
      solar equatorial plane and therefore parallel to the X(IHG)-Y(IHG) plane
      too.  The Z(HG) axis is chosen to complete the orthonormal triad.       
                                                                              
      An excellent reference guide with diagrams explaining the IHG and HG    
      systems may be found in Space and Science Reviews, Volume 39 (1984),    
      pages 255-316, MHD Processes in the Outer Heliosphere, L. F. Burlaga    
      [BURLAGA1984].