Electromagnetic (EM) energy comes from switching the positive and negative poles of a magnet back and forth. It's how we produce electrical energy. EM energy as we know it's a vector form of energy, meaning the electrons involved move from one place to another.
Conventional EM energy has a wave form, like the waves of the ocean, or when, as a kid , you shook a rope up and down and created a wave that means. These waves are transverse, meaning that the wave's energy goes in one axis (up and down), while the wave itself goes perpendicular to that, forward along the rope or in direction of the shore.
But James Clerk Maxwell in 1865, Nikola Tesla in 1899, and E. T. Whitaker in 1903 realized that there was another type of wave present together with the regular transverse EM energy, referred to as longitudinal EM energy. This form of wave energy is mentioned as scalar energy (as opposed to vector energy), as the particles associated do not travel anywhere. Another name given to the event is zero point energy.
Let me give you an example: assume you and your friends were lined up next to each other, all facing in the same direction, and the person next to you gives your shoulder a shove, not rigid enough to knock you down, but enough to bump you into the person next to you. That person will bump the person next to them, and so on. What happened? Energy was transmitted along the line of people, but no one truly went anywhere. You and your friends just created a longitudinal wave.
Longitudinal waves are also referred to as compression waves. An additional image that might help you to picture a compression wave is when you drop a stone into water and the waves spread out from that. The stone drops down (transmitting vector energy as transverse EM energy does); the longitudinal waves form 90 degrees to the stone on the surface of the water, bobbing a leaf up and down but never moving it away. It's not just the identical, but hopefully you get the idea.
So where does such longitudinal (or scalar) EM energy come from? The theory is that when electrons become part of an electrical current in conventional (transverse) EM energy, the remainder of the atom has an equal and opposite reaction in the other direction, to balance things out. The pebble drops down; the water rushes up to fill up the gap. The two opposite reactions of the electrons and their atoms causes longitudinal EM waves to develop, just as waves form after a pebble drops into water.
Since the early 20th century, several investigators have tried to develop practical applications of scalar EM energy including medical and health purposes, home-based energy production and weaponization, with varying degrees of success. Among the most recent applications has been the scalar energy pendant reported to have some health benefits.
What Do You Know About Scalar Energy? An Additional Form Of Wave Occurring With The Standard Transverse EM Energy.