Method for reduction of electron Larmor gyration radius in drift tube

Abstract

The present invention provides a method for reduction of an electron Larmor gyration radius in a drift tube. A parallel gradient magnetic field is loaded within a range of z0<=z<=z1 of a transition region in a cylindrical drift tube, electrons are subjected to the parallel gradient magnetic field of the transition region from a region with uniform axial magnetic field intensity B0 and then enter aregion with an axial magnetic field intensity B1, B1<B0, a component Br of the parallel gradient magnetic field of the transition region can achieve conversion of the transverse momentum and the axial momentum of the electrons. When the radial speeds of the electrons are outward in a radial direction when entering the parallel gradient magnetic field, the radial speeds of the electrons are inwardin the radial direction when being far away from the parallel gradient magnetic field, and the effect of parallel gradient magnetic field reduces the transverse momentum of the electrons to inhibit the radial vibration of an electron beam. The method provided by the invention is applied to a low-magnetic field O-type high-power microwave generation device to improve the wave beam interaction efficiency, effectively reduce the bombardment of a device high-frequency structure by the electrons, reduce the risk of vacuum breakdown of the strong electromagnetic field and facilitate efficient and stable operation of the high-power microwave generation device.

Description

technical field [0001] The invention belongs to the field of beam transmission and relates to a method for reducing the Larmor radius of gyration of electrons in a drift tube. Background technique [0002] The transport of electron beams in drift tubes is a fundamental problem for many physical processes. In the O-type high-power microwave generation device, the annular high-current relativistic electron beam generated by the explosive emission cathode is axially transmitted under the confinement of the guiding magnetic field, and the conversion of electron beam energy to microwave energy is completed in the high-frequency structure of the device. When the guiding magnetic field is low, the transverse momentum of the electrons due to the radial electric field causes the electrons to have a larger Larmor radius of gyration when transporting in the drift tube, resulting in significant radial oscillations, which may cause some electrons to bombard the tube wall, Seriously affe...

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Problems solved by technology

Yang Jianhua of the National University of Defense Technology adopted a guide magnetic field configuration that gradually decreases through the drift tube region in his doctoral dissertation on low-magnetic field high-power microwave generation devices (Yang Jianhua, National University of Defense Technology doctoral dissertation, 2002), and he believed that the gradually decreasing magnetic field The resulting reduction in the Larmor gyration frequency will reduce the electron's transverse momentum proportionally, but the electron Larmor gyration radius does not decrease significantly

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