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.]