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   51039
   We attempt to solve one of the hardest questions on the theory of
   pulsar magnetosphere; why millisecond pulsars operate just as ordinary
   pulsars in spite of the fact that their polar magnetic field is four
   orders of magnitude weaker? A key parameter of the magnetospheric
   particle acceleration is the magnetic field strength at the light
   cylinder. We propose to observe a millisecond pulsar B1937+21, whose
   light cylinder field is the strongest in the millisecond pulsar
   population and is as same as that of the Crab pulsar, being expected to
   exhibit X-ray pulsation from the accelerated particles. This
   observation clearly differentiates several theories for the
   relativistic particle acceleration in the pulsar magnetosphere.
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