Electricity and Magnetism
An atom’s electrons have a negative electric charge; its protons are positively charged, and its neutrons have no charge. Like charges (for example, two protons) repel each other. Unlike charges (an electron and a proton) attract. In atoms, electrons and protons are held together by their opposite electric charges. If there are equal numbers of electrons and protons in an atom, the entire atom is said to be electrically neutral. If a neutral atom loses electrons, its net charge becomes positive, and it is said to be a positive ion. If an atom acquires extra electrons, it becomes a negative ion. It really doesn’t take much to create a hydrogen ion. Even though hydrogen hangs onto its electrons better than magnesium, a little bit of ultraviolet light or an excited electron (with an energy of only 13.6 electron volts) will easily remove hydrogen atom’s only electron, and turn the hydrogen into a hydrogen ion (a proton).
When a positive electric charge moves through a wire, it produces a magnetic field, which is oriented at a right angle to the charge's direction of motion. If a compass – which always points in the direction of a magnetic field – is placed over or under a current-carrying wire, the compass will point at a right angle to the wire as shown:
If the wire is arranged perpendicular to a table top, so the current flows straight up from the table; and compasses are placed around the wire, they will show that the magnetic field is circling the wire, as shown on the right. (The “wire” is the gray arrow shown pointing “up” out of the page and a little bit to the left.) No matter which way the current-carrying wire points, the magnetic lines of force form circles around it. The direction of the circling is determined by the direction of the "+" charge's movement. If instead, the charges are negative (electrons) and are flowing in the same direction– the lines of force will circle in the opposite direction.
If electrons are moving through a magnetic field, they are always deflected at a right angle to it. Notice! A magnetic field does NOT attract or repel electrons; instead it deflects the path of an electron with a force that pushes at a right angle to both the electron’s direction, and the magnetic field’s direction (where a compass would point if it were placed in the field).
So, when an electron is fired into a magnetic field, the magnetic field pushes it sideways. However it is important to realize that after the magnetic field changes the electron’s direction of motion, the magnetic field CONTINUES to push the electron at a right angle to its motion for as long as it is in the field. In other words, the direction of the sideways force CHANGES as the direction of the electron’s motion changes! The magnetic field on the right is pointing into the page (the blue “X”s that you can see are the “tailfeathers” of the arrows.) So a magnetic field can make an electron do a 90 degree turn (as shown on the right); or even make it do a full 180 and reverse course!
If an electron is fired at a current-carrying conductor (gray arrow pointing toward the top of the page pictured on the left), the magnetic field surrounding the conductor will deflect the electron away from the conductor (the electron’s deflected pathway is shown in red). The electron cannot hit the conductor because it is deflected by the magnetic field. This is the key to “herding” the electrons into a dense negative cloud at the center of the Polywell.
If the current-carrying conductors are wound into coils of wire, the wires are still surrounded by magnetic lines of force, and the electrons are still deflected away from the conductors, as shown right.Our goal, to capture and contain a cloud of electrons, can be accomplished by arranging six of these coils of wire in a cube. The cube is given a positive charge, to attract the electrons. The magnetic fields will keep the electrons inside of the cube.