无限长密绕载流螺线管外的磁场

Magnetic field around an infinite tightly wound solenoid

螺线管是用一根长直导线绕成密集排列的螺旋线圈组成的 ,无限长密绕载流螺线管内的磁场可通过极限方法求出 ,但管外的磁场 ,教材却没有仔细讨论 .本文着重分析并解决这个问题 .

A solenoid is a series connection of coaxial wire loops of the same area.For a tightly wound solenoid,the 'leakage' lines of induction are almost impossible.This paper serve to illustrate the concepts and show the routine of problem solving.