Some of the following statements about the creation of magnetic fields are true, while others aren’t true. Depending on the type of field, magnetism can be either attractive or repulsive. So it’s possible to create an up-and-down magnetic field or a sideways one. A magnetic field can also be created by electrically charged particles traveling in a circular path around a current loop. This creates an electrostatic dipole – an entity with a region that has opposite electric charges on either side of the axis passing through it, such as an orbiting electron and proton in hydrogen gas which have their charges separated by just under 10 billionth (10e?) of a centimeter.
Magnetic fields can be created outside a vacuum, which is not so easily accomplished. In 1820 [[John Blackmore|John Blackmore]] and [[James Maxwell|Sir James Clerk Maxwell]] both independently discovered that if electric charges are placed near one another in a strong magnetic field, the electric forces will deflect those nearby charges as well. In the first part of this process, which was discovered by [[Johann Joachim Becher|Johann Becher]], it was found that these deflected charges curve around the magnetic field line in a helical manner. The part of the field line that is deflected is called a magnetic dipole. These fields can be either “up” or “down”. A negative deflection of charges in a magnetic field, such as in a laboratory compass, creates an electric current so that there appears to be an electromotive force (EMF).
A magnetic field can be created with electric charge by placing looped wires in the Earth’s magnetic field. In this way, operators can create strong magnetic fields by simply connecting some wires and shorting them out at the end to pull down on the charges. Because these charged particles are moving in a circular path around the wire ends, they will create a dipole and thus a magnetic field, just like other magnets. This was discovered by [Carl Friedrich Gauss, Samuel Winstanley and Peter Tscherning] in the 1820s.
In addition, it is also possible to create current loops that are inside a magnetic field that doesn’t contain any electric charges. As mentioned above, this could be accomplished by placing electrically charged particles in closed circuits. However, this would not necessarily create a dipole because of the lack of an electric current loop within one side of the magnetic field line. For example, electrons can be confined along a wire in the Earth’s magnetic field without producing “north” or “south” poles at its ends.
Another magnetic field can be generated by using a current loop with the wire ends placed in a fluid. The magnetic field is so weak, however, that it is called “magnetic dipole” and not “magneto-dipole”. This is an electrodynamic or electrostatic dipole, like the electric dipoles of the atom are in molecule chemistry. It was discovered by [[George Francis FitzGerald]] in 1852.
Lastly, one can make a very weak magnetism in a vacuum by placing metal filings on either side of an electromagnet of sufficient size. This is similar to the effect of iron filings near a magnet. It was a useful demonstration with which [[Michael Faraday|Michael Faraday]] would often end his public lectures.
The “magnetic field” is a region surrounding an electric current-carrying wire, with magnetic force lines (also called “flux lines”) emerging from it. Current-carrying wires are found in electric motors and generators, transformers, and electromagnets. Although most textbooks work with a simplified model of a “straight wire,” in fact, the real world has nothing straight. The field of a wire actually resolves to space curves called [[Maxwell’s Equations|Maxwell’s magnetic field]], and the wires are always curved. Remarkably, however, although they are usually not straight, all the lines are in closed curves.