Study On The Transport Of Foil-Focused Radial Intense Relativistic Electron Beam

The measure transporting intense relativistic beam by transverse conducting foils has many advantages, for example, it do not need leading magnetic filed ,it works well without consuming any power ,its configuration is simple and price is cheap .Most of all it can cut down the volume and weight of the HPM generation mechanisms maximally . And this measure has been used for focusing axial intense relativistic beam successfully . In this paper , this measure will be used for focusing radial intense relativistic beam in radial HPM generation mechanisms , and the academic study and discuss will be made about how many intension the radial excursion space can transport and how to choose appropriate parameter for focusing radial intense relativistic beam .Firstly , according to the characteristic of the intense relativistic beam in excursion space, some proper predigestion and hypotheses will be made, and the appropriate physics model will be given ; then depending on the equation which the electrons of the beam satisfy in the excursion space of the model, a iterative arithmetic for calculating the electric potential of the beam in the excursion space is given, then its constringency and its validity are proved.Based on this arithmetic , a method for calculating the space-charge limiting current is found . Then the space-charge limiting current in the radial excursion space is calculated , the figure about the beam intension as a function of the minimal kinetic energy of the beam electron is plotted , and the principle for judging the range about the space-charge limiting current in the radial excursion space is gotten . In addition , for any excursion space in any orthogonal curvilinear coordinate , the electric potential , electric field of the beam and the space-charge limiting current can be calculated by using this arithmetic if the transverse of the beam is known and the beam satisfies the predigestion and hypotheses of the model.Based on the calculating of the electric filed and magnetic filed about the beam across through the excursion space , the balance equation for foil-focused radial relativistic electron beam is gotten , the stability of the equilibrium is discussed , and the method for calculating the track of those electrons in the beam's brim as well as the parameters interrelated are given ,then the principle for chosen the distance between focusing foils is given by combining the balance equation and the request of the track.When the intension of beam is sparse the change of the beam electron's velocity as well as the infection for the electron's density aroused by the change of the beam electron's can be ignored . In this condition , the analytic formula of the electric field is gotten ,then the he balance equation , the track of those electrons in the beam's brim and their parameters interrelated are presented .Lastly , the rang in where the change of the beam electron's velocity can be ignored is given. Using the analytic formula of the electric field can reflect the physical orderliness interrelated clearly as well as save calculating time and computer resource greatly.