The Design Of The Gyrotron Magnetron Injection Gun

The Gyrotron have a wide range of applications in radar,electronic warfare,plasma heating,controlled thermonuclear fusion, high-energy physics, new materials with the superior amplification and oscillation performance in the millimeter and submillimeter bands. Because people do not know how to effectively reduce the velocity spread, the generation of high-quality axis-encircling electron beam is difficult compared with the formation of the small-orbit electron beam.A new method to design the magnetic field is developed.The Magnetic field can reduce the radial velociry at the anode region which is the key to achieve small beam velocity spread.the matlab code is used to cosimulate the trajectory of single-electron in the cusp electron gun.The result s of the PIC3D simulation is the annular-shaped axis-encircling electron beam has a beam beam current of1.5A at an acceleration potential of30kV,a tunable velocity ration2-2.4,a axial velocity spread of～12%,a tangential velocity spread of～4%. The relationship between radial velocity and velocity spread, width of the Cathode and velocity spread,is discussed.It is also show that the the similar approach to design the magnetic field of a small-orbit electron gun.The designed magnetic field can accurately control the electronic radial acceleration, and increase the electron radial velocity. The results of the numerical simulation of single electron cyclotron movement and the PIC simulation of a small-orbit electron beam meet the requirements. The Difference of the small-orbit electron beam and axis-encircling electron beam is discussed.