Magnetic field measuring method and magnetic field measuring apparatus

A magnetic field measuring apparatus with which a combination coil provided with a plurality of coils having a common coil axis is used as a measuring target coil, and by which an inter-coil center position where a radial-magnetic-field distribution along the coil axis of the measuring target coil is up-down symmetric about a plane perpendicular to the coil axis, is determined while using, as an offset axis, a direction that is parallel to the coil axis and at an offset position radially apart by a set length from the coil axis, the magnetic field measuring apparatus comprising:

• a magnetic field sensor by which intensities of radial magnetic fields at the offset position are measured;
• a rotary table on which the magnetic field sensor is mounted at the offset position radially apart by the set length from the coil axis;
• and
• data processing circuitry configured to calculate the inter-coil center position on the basis of the intensities of the radial magnetic fields measured by the magnetic field sensor;
• wherein the data processing circuitry is further configured to
• receive the intensities of the radial magnetic fields measured by the magnetic field sensor;
• calculate a first radial-magnetic-field distribution along the offset axis, on the basis of the intensities of the radial magnetic fields at the offset position, that are inputted from the magnetic field sensor placed at the offset position;
• calculate a second radial-magnetic-field distribution along the offset axis, on the basis of intensities of the radial magnetic fields at the offset position, that are inputted from the magnetic field sensor after being rotated at the offset position by a set angle around the offset axis by the rotary table;
• and
• determine the inter-coil center position on the basis of the calculated first radial-magnetic-field distribution and the calculated second radial-magnetic-field distribution.