| Popis: |
A charged particle of mass m moving with velocity V z through a continuous medium approximately parallel to a uniform magnetic field H suffers many small-angle Coulomb scatterings. The net square displacement in one traversal can be expressed as a sum of the square displacements from single scattering occuring in many independent traversals. These single displacements have been evaluated by beam transport methods, and the ratio of the net rms displacement projected on a plane perpendicular to the magnetic field to the zero field displacement is found to be F = [ 6 Φ 2 ( 1− sin Φ Φ )] 1 2 , where Φ = eHz/ (mV z c) is the angle of the helical trajectory, e.g. for a single-turn helical trajectory, F (2 π ) = 0.4, and the effect of the magnetic field is to reduce the multiple scattering to 40%. This confirms the solution of the diffusion equation for the distribution function due to Farley, Fiorentini and Stocks. |
