Compact magnet system for a high-power millimeter-wave gyrotron

A compact magnet system for a high-power microwave tube comprising:

• a first tubular retaining member having an inner wall, the first tubular retaining member made of a material selected from the group consisting of iron, a permanently magnetic element, stainless steel and aluminum, the first tubular retaining member defining a central axis;
• a solenoid coil fitting within the first tubular retaining member, the solenoid coil defining a central cavity of radius r1 along the central axis, the solenoid coil having a coil width defined by a first side and a second side;
• a plurality of first permanent magnets positioned to extend radially from the central axis beginning at or below radius r1 so that the plurality of first permanent magnets wraps around the central axis along the first side of the solenoid coil;
• each first permanent magnet in the plurality of first permanent magnets comprises a first magnetic north pole and a first magnetic south pole wherein the same pole faces the central axis;
• a plurality of second permanent magnets positioned to extend radially from the central axis beginning at about radius r1 so that the plurality of second permanent magnets wraps around the central axis along the second side of the solenoid coil;
• and
• each second permanent magnet in the plurality of second permanent magnets comprises a second magnetic north pole and a second magnetic south pole wherein the pole that faces the central axis is opposite to the pole of the plurality of first permanent magnets facing the central axis.