electromagnetic compatibility

At night on a volcano summit, six telescopes stare at the same speck of light. Each catches its own copy of the wave, and if you combine their signals, you get an image that no single instrument could produce alone. But there's a catch: light captured by different stations cannot simply be added like photographs.

The electron beam of a microscope usually flies through emptiness, like a courier on an empty highway. Any air molecule is a bump that makes it bounce and lose direction. So before, to examine a sample, you had to freeze it, dry it, or coat it with metal—and still you could only look in a vacuum.

An electrocardiogram is like a recording of a conversation where the heart whispers and a construction site roars in the background. Atrial fibrillation, where the atria quiver instead of contracting, changes that whisper almost imperceptibly.

The magnetic field in this setup must be as smooth as glass: the slightest ripple would blur the signal. The engineers built two coils that cancel each other's field externally and packed them in three layers of ferromagnetic plates.

The coil in an MRI picks up radio signals from hydrogen atoms, like an antenna catching a distant radio station. But the signal is weak, and if the amplifier itself is noisy, the image comes out grainy.

A magnetic mirror is a tube open at both ends. The magnetic field inside is arranged so that hot plasma doesn't leak out: at the ends, the field lines bunch up like a cork in a bottle. Plasma particles flying toward the exit are repelled by these "corks" and bounce back. But some still escape: that's the classic "loss cone" argument.

The brain is an orchestra where each group of instruments must come in on time. In Alzheimer's disease, the musicians lose their notes: connections between brain regions get tangled, and the harmonious performance turns into cacophony. Scientists have long seen these disruptions on scans, but they didn't know if the situation could be fixed by touching just one string.

An eye prosthesis sends the brain not a photograph but a sparse pattern of bright dots — phosphenes. To make out a cup or keys in this flickering noise, a person has to move their head like a flashlight in the dark, piecing together the object's outline bit by bit. It's a slow process, like assembling a puzzle where most pieces have been thrown away.

A thin sandwich made of two different materials. You run an electric current through it, and the top slice magnetizes in one direction, the bottom in the opposite. This isn't a magic trick; it's the layer Edelstein effect, just described by physicists.

Electricity from the wall socket isn’t steady noise; it’s a wave pulsing 50 times a second. Every gadget at home has to sync with this rhythm, or chaos would break loose. To keep the beat, power grids use a phase detector — a “smart ear” that listens to the voltage like a musician tuning into a note.

The power grid is often compared to a water supply: current flows like water under pressure. Electric vehicles here are powerful pumps, capable not only of pumping water (charging) but also pushing back when needed, evening out the pressure. The trouble is, solar panels generate energy in surges, like a pump that gulps and then blasts with double force.

Used EV batteries behave like moody musicians: one plays too loud, another too soft, a third goes out of tune for no reason. Slapping them together randomly creates a cacophony: some cells get overloaded, others sit idle, and the system fails quickly. Engineers turned this problem into a conductor's challenge.

A Tesla coil crackles, and a beam of light begins to rotate around it. The medium it passes through is still stable, but the field grows, and the rotation intensifies. This is not a trick but the behavior of special materials that couple electricity and magnetism. For such coupling, there is a fundamental limit — the Tellegen limit.

A sheet of paper with square grid, one with diamond grid, and one with honeycomb — three different universes for an ant. Change the sheet, and the rules of movement change. That's roughly how electrons experience the crystal lattice: geometry dictates whether they become little magnets, superconductors, or something else. In ordinary materials, the lattice is as rigid as if engraved.

The powerful magnet of an MRI scanner induces weak electric currents in tissues. Their phase behaves like a compass needle trembling with every gust of wind — the slightest disturbance turns the map into a ripple, where instead of small vessels or iron deposits, all you see is noise.

A rubber band that gets thicker the harder you pull it. In electricity, this behavior is called negative capacitance: the more charge accumulates on the plates, the lower the voltage. A regular capacitor works the opposite way — voltage rises with charge.

Quantum laws reign supreme in the microworld, but macroscopic objects usually behave classically: the thermal motion of atoms drowns out quantum effects.

Two electrically charged spheres attract each other with a certain force. If you replace their charges with magnetic poles, a spring scale shows exactly the same force. Black holes, it turns out, behave the same way — except instead of springs, the fabric of spacetime itself does the work.

Imagine a huge swimming pool. In one corner, a chemical reaction is underway that needs to be calculated with jeweler-like precision. But the surrounding water is not just decoration: its molecules jostle, attract, and influence the reaction. How do you account for this endless dance of particles without drowning in calculations?

A person hears a ringing that isn't there. The doctor asks them to describe it — loudness, pitch, persistence. But it's subjective: one might say "like a mosquito," another "like steam from a kettle." We need a way to see tinnitus directly, in the brain itself.

In an empty hall, sound bounces between walls, turning into a booming echo. An optical cavity is the same echo chamber, just for light.

An orchestra where each musician plays their own part but hears only the neighbor. One wrong note, and a wave of errors rolls through the hall. That's how Ising machines work — special devices for solving problems where you need to find the best option among many.

The edge of a magnet works like a guitar fret: a string pressed near the edge sounds different, with a richer set of overtones. Magnetic waves in a thin strip of nickel and iron behave in much the same way.

Radio waves surround us, but our eyes can't see them. This new sensor, the size of a fingernail, turns them into a colored patch on a tiny screen. Inside the chip is a layer of liquid crystals — the same kind used in phone displays. Among them are embedded thin ferromagnetic nanowires. When a radio wave arrives, the nanowires heat up quickly.

Depression is sometimes sought in the brain's electrical waves. The logic is simple: if a disease has stages (acute, maintenance, recovery) then the signals should change gradually, like volume when you turn a knob. Researchers took EEG recordings from 74 people: 24 in the acute phase, 23 in the maintenance phase, and 27 healthy.

An ordinary rubber strip filled with fine iron filings doesn't just bend in a magnetic field: it ties itself into a stable knot. This effect was predicted and reproduced in experiments by physicists working with magnetoactive elastomers: a silicone base with carbonyl iron particles.

Plasma in a fusion reactor is like a swarm of fireflies that you need to keep inside an invisible jar. It used to be thought that the jar's walls had to be perfectly smooth, or the fireflies would find a crack and escape. New work shows that the jar can be glued together from pieces with noticeable seams, and the swarm will still stay inside.

A fusion reactor is like an orchestra, where the plasma is the melody and the magnetic coils are the musicians. If one instrument plays out of tune, the whole symphony falls apart.

Quantum devices usually live inside cryostats — giant thermoses where temperatures are colder than deep space. An erbium ion trapped in a tiny well on a silicon chip breaks that mold.

Gravity works like an invisible photographer. When a piece of metal falls, inside it, according to Albert Einstein and the electromagnetism of James Clerk Maxwell, an electric field is born — that's how spacetime curvature…