visualising magnetic fields

[...]... poles attract, and therefore magnetic lines of force are directed away from the north pole of a magnet and towards the south pole In fact, although scientists have searched for, and are still searching for, isolated magnetic poles (i.e magnetic monopoles), they have never been discovered The magnitude and direction of a magnetic field is B, the magnetic flux 8 Physics of the magnetic field Figure 2-1:... equations showed that electric and magnetic fields were inextricably entwined, and it is not surprising that (for linear materials) there are close analogies between electric and magnetic quantities A system comprising one or more flux sources and magnetic materials is called a magnetic circuit and, just like an electric circuit, with voltages, resistance, currents, etc., magnetic circuits can be analysed... in visualisation The analogies between electric and magnetic circuits are so close that it is a reasonable assumption that an electric circuit analysis method might be extended to solve magnetic circuits In creating a complete methodology for visualising magnetic fields, the first step is to find a technique that can provide a representation of the magnetic field line patterns and a method to do this,... magnets, coils and magnetic materials, and sketch how they think the lines of magnetic force will link everything together They try to gain an intuitive feeling for the behaviour of the system, as a precursor to moving to a full quantitative analysis on a suitable computational platform Thus magnetic lines of force are as useful a concept to us today, in the visualisation of magnetic fields, as they were... density When we draw magnetic field lines to represent a magnetic field, the direction of the line at any point is tangential to the direction of the magnetic flux density, and the magnitude of the field is proportional to the number of field lines per unit area There are two important rules to remember about magnetic field lines: first that field lines can never cross, and second that magnetic field lines... We can see that magnetic field lines near the centre of the coil have nearly uniform spacing, showing that the magnetic flux density (B) is nearly constant in magnitude and direction At the ends of the coil the magnetic field lines are more widely and less uniformly spaced, and for a long solenoid the magnetic flux density on axis at the ends is half that at the centre Physics of the magnetic field... the magnetic field of a material is linearly dependant on the external field However, it is still possible to use a linear model to assess the performance of magnetic systems, because many systems are designed to operate in the linear region, and points of high magnetic flux density, where saturation would first occur, are easily seen A linear model is nearly always the first step in visualising a magnetic. .. the modelling method and the algorithms, the next chapter gives a brief review of the physics of magnetic fields, and illustrates the principles with magnetic field plots made using the VIZIMAG application This Page Intentionally Left Blank 2 Physics of the magnetic field The properties of magnetite, the magnetic ore of iron, have been known since ancient times, and this has made the study of magnetism... with the path of the flux shown by the magnetic field lines The permeability of the coil, magnetic domain material in the core, and the air gap form the reluctance elements of the magnetic circuit and (together with leakage flux into the surrounding air) determine the total amount of flux produced Figure 2-10: Magnetic circuit with air gap 18 Physics of the magnetic field The first step in visualisation... textbooks available Fields and field lines A bar magnet, or a wire carrying a current, produces a magnetic field permeating the space all around it The direction of the field at any point is defined to be the direction in which a north magnetic pole would move due to the field at that point, and the path through which this pole would freely move is the magnetic line of force or magnetic field line .