Cylindrical permanent magnet unit suitable for gyrotron

A cylindrical permanent magnet unit suitable for application to gyrotrons, comprising:

• a first cylindrical permanent magnet which is an assembly of a plurality of coaxially juxtaposed ring-like permanent magnets each of which is magnetized in approximately radial directions from the inside toward the outside;
• a second cylindrical permanent magnet which is an assembly of a plurality of coaxially juxtaposed ring-like permanent magnets each of which is magnetized in approximately radial directions from the outside toward the inside, wherein
• the first and second cylindrical permanent magnets are longitudinally aligned to have a common center axis and to provide a space between the first and second tubular magnets, each of the ring-like permanent magnets of the first and second cylindrical permanent magnets being constructed of a plurality of segments arranged around a circumference, each of said segments being a permanent magnet magnetized in an approximately radial direction with respect to said circumference;
• and
• an auxiliary ring-like permanent magnet which is inserted in the space between the first and second cylindrical permanent magnets and is magnetized in a direction parallel to said center axis.

A cylindrical permanent magnet unit suitable for application to gyrotrons, comprising:

• a first cylindrical permanent magnet which is an assembly of a plurality of coaxially juxtaposed ring-like permanent magnets each of which is magnetized in approximately radial directions from the inside toward the outside;
• a second cylindrical permanent magnet which is an assembly of a plurality of coaxially juxtaposed ring-like permanent magnets each of which is magnetized in approximately radial directions from the outside toward the inside, wherein
• the first and second cylindrical permanent magnets are longitudinally aligned to have a common center axis and to provide a space between the first and second tubular magnets, each of the ring-like permanent magnets of the first and second cylindrical permanent magnets being constructed of a plurality of segments arranged around a circumference, each of said segments being a permanent magnet magnetized in an approximately radial direction with respect to said circumference;
• and
• at least one of the ring-like permanent magnets in the first and second cylindrical permanent magnets comprises a plurality of elongate pieces of a ferromagnetic material which are adjustably inserted into the respective segments of the ring-like permanent magnet in approximately radial directions from the outside.