The generation of very intense magnetic fields

The paper describes a method for generating magnetic fields of the order of magnitude of 1 million gauss, and for impressing such fields on a specimen of magnetic material at regular intervals, with a view to ascertaining whether any disturbance of the electronic orbits could be obtained of sufficient magnitude to produce a marked effect on the magnetization curve of the specimen. An account is given of the means used for measuring the magnitude and frequency of the heavy transient currents to which the intense magnetic fields are due. The influence of the dimensions of the solenoid through which the transient currents flow is considered as determining the intensity of the magnetic field produced. A comparison is given of the calculated and measured values of the transient currents for three different solenoids. It is found that, whilst the calculated values agree well with the measured values for solenoids with a relatively small number of turns of thick wire, there is an appreciable discrepancy in the case of a solenoid with a large number of turns of thin wire. An attempt is made to explain this discrepancy as due to the condenser effect of the contact E.M.F. between the copper wire and the oil-soaked cotton insulation which is in contact with the wire.