Analysis On Field Distribution Characteristics Of Limited Solenoid

In the field of electromagnetism, people have some re levant theoretical derivation and numerical analysis on current-carrying round wire, unlimited solenoid, and tightly-winding limited solenoid. However, the solenoid is not ideal tightly- winding in the practical production, and there will be higher requirements for calculating the magnetic field in this case. Based on the Biot-Savart’s Law and the Superposition Theorem, the distribution of magnetic field in the limited solenoid on alternating current is analyzed by using the numerical method in this paper.According to the basic theory and the analyzing method of electromagnetic field, the calculation methods of magnetic field in the limited solenoid on steady current are analyzed and discussed. Firstly, the advantages and disadvantages of three different methods to calculate magnetic field are compared and analyzed. Secondly, the magnetic field calculation model of basic coil in the magnetic field calculation of usual solenoid is introduced, and the analytical expression of magnetic field on the field point o f axis is derived. Then the magnetic field distribution of a limited long solenoid with steady current is analyzed. The computational model of current decomposition and the computational model of consider screw-pitch is introduced. The advantages and disadvantages of the two computational model is discussed.Further, according with the basic theory of calculation model of magnetic field in the solenoid, the magnetic field distribution in the limited solenoid with alliterating current is analyzed and discussed. The magnetic field distribution in the plane vertical of the solenoid axis is analyzed, and the three-dimensional profile of magnetic field distribution in the cross-section and the field distribution projected in the three orthogonal planes are given. At the same time, the variation of field distribution in the plane parallel to and across the axis of solenoid is analyzed, and the three-dimensional profile and the field distribution projected in the orthogonal planes are obtained, too.