The effects of a beam thickness and a conducting wall in a free electron laser with a linearlypolarized wiggler magnetic field and an axial magnetic field are investigated within the framework of fluid-Maxwell equatio...The effects of a beam thickness and a conducting wall in a free electron laser with a linearlypolarized wiggler magnetic field and an axial magnetic field are investigated within the framework of fluid-Maxwell equations.The growth rate of free electron laser instability is obtained,in which the nonlinear bulkand surface current density are simultaneously considered.The numerical calculations indicate that the bulkcoupling is dominant.There is an optimum beam thickness and separation between the conducting walls forwhich the growth rate is maximum.展开更多
Properties of coherent radiation of millimeter waves generated by an intense rotating annularrelativistic electron beam(E-layer)which is from a cusp magnetic field are investigated.The linearizedVlasov-Maxwell equatio...Properties of coherent radiation of millimeter waves generated by an intense rotating annularrelativistic electron beam(E-layer)which is from a cusp magnetic field are investigated.The linearizedVlasov-Maxwell equations are used to analyze the interaction between E-layer and resonators of themagnetron.The dispersion relation is deduced and numerical calculation is made.The results show that thefrequency of microwave radiation is ω_r(ω_r=lΩ〃 where Ω〃 is the electron relativistic cyclotron frequencyin the axial magnetic field;l is the azimuthal mode number,l=n+mN;N is the number of sideresonators,n=0,1,2,……N/2,m is any integer).The growth rate of radiation is still large enough even ifl is large.It is good for generating a millimeter wave radiation at low axial magnetic field.If the modes canbe controlled well,a tunable,high power millimeter wave device can be made.展开更多
文摘The effects of a beam thickness and a conducting wall in a free electron laser with a linearlypolarized wiggler magnetic field and an axial magnetic field are investigated within the framework of fluid-Maxwell equations.The growth rate of free electron laser instability is obtained,in which the nonlinear bulkand surface current density are simultaneously considered.The numerical calculations indicate that the bulkcoupling is dominant.There is an optimum beam thickness and separation between the conducting walls forwhich the growth rate is maximum.
文摘Properties of coherent radiation of millimeter waves generated by an intense rotating annularrelativistic electron beam(E-layer)which is from a cusp magnetic field are investigated.The linearizedVlasov-Maxwell equations are used to analyze the interaction between E-layer and resonators of themagnetron.The dispersion relation is deduced and numerical calculation is made.The results show that thefrequency of microwave radiation is ω_r(ω_r=lΩ〃 where Ω〃 is the electron relativistic cyclotron frequencyin the axial magnetic field;l is the azimuthal mode number,l=n+mN;N is the number of sideresonators,n=0,1,2,……N/2,m is any integer).The growth rate of radiation is still large enough even ifl is large.It is good for generating a millimeter wave radiation at low axial magnetic field.If the modes canbe controlled well,a tunable,high power millimeter wave device can be made.
