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PDS_VERSION_ID                 = PDS3                                         
LABEL_REVISION_NOTE            = "Initiated        JMAFI, 2004-03-01"         
                                                                              
OBJECT                         = INSTRUMENT                                   
  INSTRUMENT_HOST_ID           = P11                                          
  INSTRUMENT_ID                = HVM                                          
                                                                              
  OBJECT                       = INSTRUMENT_INFORMATION                       
    INSTRUMENT_NAME            = "HELIUM VECTOR MAGNETOMETER"                 
    INSTRUMENT_TYPE            = "MAGNETOMETER"                               
    INSTRUMENT_DESC            = "                                            
                                                                              
  Instrument Overview                                                         
  ===================                                                         
    Magnetic fields affect the plasma of electrically charged particles       
    in interplanetary space and control the flow of this plasma as it         
    spreads out from the Sun across the orbits of the planets. Before         
    the mission of Pioneer 10 these effects had been only observed and        
    measured out to the orbit of Mars. Scientists were still uncertain        
    about many specific details about the interplanetary medium and           
    particularly the extent to which the Sun's magnetic field controlled      
    the flow of plasma beyond Mars to the outer regions of the Solar          
    System. The outer boundaries of this influence were vague, and            
    interactions between the plasma and fields of the Solar System and        
    those of the Galactic System puzzled scientists. Pioneer 10 and           
    Pioneer 11 explored the regions beyond the orbit of Jupiter and made      
    measurements that helped to define the transition region of solar         
    influence (heliosphere).                                                  
                                                                              
    This experiment used a sensitive magnetometer at the tip of a             
    lightweight boom, which extended 6.6 meters from the center of the        
    spacecraft to reduce the effects of the residual spacecraft magnetic      
    field, and to assist the balance of this spin stabilized spacecraft.      
    The helium vector magnetometer measured the fine structure of the         
    interplanetary field, maped the Jovian field, and provided field          
    measurements to evaluate solar wind interaction with Jupiter. The         
    magnetometer operated in one of eight different ranges, the lowest        
    of which covered magnetic fields from +/-0.01 to +/-4.0 gamma; the        
    highest, fields up to +/-140,000 gamma (i.e. +/-l.4 Gauss). The           
    ranges were selected by ground command or automatically by the            
    instrument itself as it reached the limits of a given range.              
                                                                              
    The sensor for the magnetometer consisted of a cell filled with           
    helium that is excited by electrical discharge at radio frequencies       
    and infrared optical pumping. Changes in helium absorption caused by      
    magnetic fields passing through the magnetometer are measured by an       
    infrared optical detector.                                                
                                                                              
  ['Instrument Overview' was adapted from FIMMELETAL pp. 49-50.]"             
                                                                              
  END_OBJECT                   = INSTRUMENT_INFORMATION                       
                                                                              
  OBJECT                       = INSTRUMENT_REFERENCE_INFO                    
    REFERENCE_KEY_ID           = "FIMMELETAL1977"                             
  END_OBJECT                   = INSTRUMENT_REFERENCE_INFO                    
                                                                              
  OBJECT                       = INSTRUMENT_REFERENCE_INFO                    
    REFERENCE_KEY_ID           = "SMITHETAL1974B"                             
  END_OBJECT                   = INSTRUMENT_REFERENCE_INFO                    
                                                                              
END_OBJECT                     = INSTRUMENT                                   
END