What you see in this photo is the result of a device called the Coin Reducer. The coin changer uses a process known as "high speed metal forming", which creates extremely powerful pulsating magnetic fields.
The experimenters used these fields to compress the coin, causing it to rapidly decrease in diameter. In the process, there is no direct contact with it - all changes are made only by an invisible and extremely strong magnetic field.
The coin reducer sends a huge current pulse (up to 100,000 amperes) into a coil made of shielded copper wire. The coin is then placed in the center of the coil.
As a result, a huge electric current is induced inside the coin. The instantaneous power applied to a coin is comparable to the total power consumption of an average city. Another phenomenon known as the "surface effect" causes this incredibly powerful current to flow within a circular ring that is only about a millimeter along the edge of the coin.
The circulating current within this ring creates another powerful magnetic field around the coin. The fields of a working coil and a coin are opposed to each other in accordance with Lenz's law. This induces tremendous magnetic repulsion forces between the coil and the coin.
Compression forces compress the coin inward, making it smaller and thicker at the same time. The whole process takes less than the blink of an eye - about 25 millionths of a second. As a result of rapid mechanical deformation and resistive heating, the coin becomes extremely hot. But after compression, it retains all images printed on it and is easily recognizable.
A compressed coin has the same mass, volume, and density as the original - as its diameter decreases, it becomes much thicker. And the degree of "compression" depends on the amount of energy imparted to the coil - more powerful pulses allow the creation of smaller coins. Equal in power, but oppositely directed forces act on the coil itself.
The intense magnetic pressure pushes the inside of the coil outward, expanding its diameter, which eventually leads to its explosion, which can be extremely dangerous (pieces of copper wire in this case act like shrapnel). The scattering pieces of the exploded wire reach a speed of one and a half kilometers per second. Therefore, to protect nearby objects and people, the whole process is carried out inside a bulletproof chamber.
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When the coil disintegrates, the residual electrical energy dissipates in the form of a bright blue-white plasma ball and shockwave. For this reason, the coins are reduced one at a time. Shrinking each coin requires hand-crafting a very precise coil, which will be destroyed in the process.