Permanent magnet quadrupole magnet with adjustable magnetic field

The invention discloses a four-pole permanent magnet with an adjustable magnetic field, which comprises four four-pole magnet pole heads which are uniformly distributed at an oblique angle of 45 degrees, four permanent magnet blocks which are uniformly distributed at a right angle of 90 degrees and are arranged at intervals with the four-pole magnet pole heads, and a circle of inner iron yokes and a circle of outer iron yokes are also arranged at the peripheries of the four four-pole magnet pole heads and the four permanent magnet blocks, a non-magnetic supporting framework is arranged between the inner iron yoke and the outer iron yoke; cuboid gaps used for magnetic field adjustment are reserved in the positions, close to the large radius, of the four permanent magnet blocks respectively and used for arranging field adjusting blocks, the field adjusting blocks can linearly move in the reserved gaps in the radius direction, and the field adjusting blocks and the field adjusting blocks form a short-circuit loo