plasma

A swing that rocks on a sawtooth hill behaves strangely: without kicks, it gets stuck in the first dip, but with rhythmic pushes it can move uphill, downhill, or stay frozen in place. That is exactly what physicists saw when they placed a single dust grain in a trap with a sawtooth bottom and started pushing it alternately with laser beams.

In a ring-shaped channel between two toothed rings, microspheres are suspended: some with a radius of 8 micrometers, others 14. The discharge is switched on, and the particles start moving. The small ones go one way, the large ones the other. It is like a shopping mall where escalators for people of different heights run in opposite directions.

A swing that rocks on a sawtooth hill behaves strangely: without kicks, it gets stuck in the first dip, but with rhythmic pushes it can move uphill, downhill, or stay frozen in place. That is exactly what physicists saw when they placed a single dust grain in a trap with a sawtooth bottom and started pushing it alternately with laser beams.

In a ring-shaped channel between two toothed rings, microspheres are suspended: some with a radius of 8 micrometers, others 14. The discharge is switched on, and the particles start moving. The small ones go one way, the large ones the other. It is like a shopping mall where escalators for people of different heights run in opposite directions.

Two caravans travel toward each other along a narrow road. One is wide and slow, carrying a load of density. The other, a string of light carts carrying current, slips between the first. Thus, in a magnetron discharge, two structures rotating in opposite directions coexist: the density spoke and the current filaments.

A laser pulse slams into a gas cloud and knocks electrons out of it, leaving behind a bubble: a cavity almost devoid of particles. This bubble races through the plasma at nearly the speed of light, and its walls drag along the electrons trapped inside, much like a speedboat tows a water skier.

A navigator with a paper chart plots the route before setting sail. If the ocean changes—the current shifts, the wind picks up—the chart stays the same. The ship follows an outdated path, and the crew has to correct the course by hand.

In 1054, a star flared up in the constellation Taurus. The light of its death was so bright that it was visible in daylight for nearly a month, and Chinese astronomers recorded it in their chronicles. Today, the Crab Nebula is spreading over that spot, and its claws are clouds of gas still being whipped up by the dead star at its center.

The Sun has a layer called the chromosphere, sitting just above the visible surface. Bright arcs often flare up there, visible through telescopes, but to understand what ignites them, you need to look at invisible magnetic fields.

Plasma is a gas in which electrons are stripped from atoms and roam freely. Sometimes, regions where electrons are almost absent spontaneously appear in such a gas; they are called holes. It is like a whirlpool forming in a stream, pulling everything around it in. But exactly how such a whirlpool is born has long remained a mystery.

A copper plate the size of a coin vaporizes under the laser's strike in billionths of a second. The hot copper cloud slams into cold helium like a jet of steam into frosty air. The images show a distinct bubble with thin filaments at the edges — the plasma doesn't expand uniformly but breaks into fibers as thin as a human hair.

In a pot of boiling soup, light fat droplets rise to the top, while heavy vegetable chunks sink to the bottom. Particles in the tenuous hot gas around the Sun and other stars behave much the same way — except instead of broth, there's a mixture of charged particles: electrons, protons, and alpha particles.

To probe deeper into the workings of the universe, physicists accelerate electrons and smash them together. An ordinary electron is like a spinning top that wobbles randomly. For delicate experiments, you need particles whose spins all point in the same direction: this is called polarization.

The Sun is a giant cauldron where light struggles through a thick layer of scorching matter. On its way out, photons (light particles) constantly bump into atoms and lose energy. How strongly matter holds back light is called "opacity," and it determines how quickly heat escapes. Iron is one of the main culprits for opacity in the Sun's interior.

Boiling water in a pot is a good place to start. Bubbles of steam rise, pop, and the surface settles down. Something similar might have happened in the first moments of the universe's life with a special field filling space: bubbles of a new phase inflated and collided, like islands of steam in liquid.

Plasma is not just hot gas; it's an entire orchestra of charged particles, each group playing its own part. Heavy ions (atoms that have lost electrons) set the slow rhythm, while light electrons dart around ten thousand times faster.

Benzoyl peroxide, the familiar ingredient in acne creams, does more than dry out skin. It releases active oxygen that tears apart bacterial membranes. But on its own, it sometimes lacks the punch. A helping hand can come from cold plasma: ionized gas at nearly room temperature.

A waterfall that doesn't heat up from the fall but freezes — that's roughly how gas behaves as it flows onto a neutron star in an X-ray pulsar when the star shines dimly. Usually, infalling matter is heated to a white-hot glow, but new work shows the opposite.

In a world locked in a crystal lattice and cooled nearly to absolute zero, matter knows how to hide its deepest secrets. A quantum spin liquid is a state where electron spins never freeze, even at zero temperature, remaining in an eternally flickering superposition.

Inside planets and stars, in rotating oceans of plasma, turbulent flows, Coriolis forces, and magnetic tension collide. The central question is how the energy of this chaos crystallizes into a stable magnetic framework that can last billions of years.

A proton bunch flies into a plasma cloud, and leaves behind an invisible trail: an electric wave. This wave can pick up other particles and accelerate them to enormous energies. But controlling it is tricky: there are too many details in plasma behavior.

Inside a fusion reactor, plasma rages — a gas heated to millions of degrees. There are no direct windows, and cameras and sensors quickly fail. Engineers see only fragments of information: a few sensors at scattered points. It's like trying to grasp a symphony from the sound of three microphones in a vast hall.

In the vast clouds of rarefied gas that fill the space between stars, something is always churning. Supernova explosions, colliding streams — all of it shakes the plasma. And in this rippling, as it turns out, hides the mechanism that gives birth to magnetic fields. Plasma is a gas in which electrons are stripped from atoms.

A typical laser is a cavity where light bounces between mirrors and gets amplified. But you can ditch the mirrors and make light circulate inside a tiny particle smaller than the light wave itself. That's how the new lasers work: nanoparticles of indium phosphide sitting on perfectly smooth gold.

Tiny seeds of life can cross the black void on icy wanderers like comet 3I/ATLAS. The James Webb Space Telescope found water and methane on it for the first time, and light analysis revealed an unusual gas composition.

Superheated gas under pressures of millions of atmospheres, like at the center of Jupiter or inside a laser target, behaves in tricky ways. Electrons are ripped from atoms and form a shared cloud that continuously reshapes itself. To simulate such a state on a computer, one usually solves cumbersome equations for each electron.

A factory laser that cuts and welds metal on production lines has been made to work as a particle accelerator for the first time. Physicists took a standard ytterbium laser, its heart is a crystal the size of a palm, and turned its flashes into a tool for accelerating electrons to nearly the speed of light.

Space is full of invisible sprinters — particles racing nearly at the speed of light. They are caught in the solar wind, near neutron stars, and even in the intergalactic void between galaxies. But what accelerates them where there are no shock waves or magnetic reconnections?

A crowd is trapped in a narrow corridor between two rows of mirrors. Every now and then, someone shoves the wall hard, and a rumble rolls down the corridor — similarly, in the plasma of galaxy clusters, whistler waves and ion-cyclotron waves appear.

Imagine a powerful hair dryer that blows not warm air but white-hot plasma, such devices are called plasma wind tunnels. They are used to test on Earth how a spacecraft will enter the atmosphere.

Just after the Big Bang, clumps weighing as much as a trillion Suns and with an electric charge of colossal strength, like trillions of electrified balloons, could have drifted through space.

When matter is heated to millions of degrees, it turns into plasma — a mix of free electrons and ions, like a boiling soup of charged particles. You can't measure the temperature of such a 'soup' with an ordinary thermometer, but you can shine X-rays through it.

A stream of electrons enters plasma like a jet of water hitting a calm pond. The jet disturbs the surface, giving rise to waves that grow quickly and mix the water. In plasma, this process is called the Buneman instability: the electron beam excites oscillations that then scatter its energy.

A dust grain hangs in the air, held by an invisible beam of light. Around it is ordinary air, but sometimes a tiny spark jumps across the grain. For the first time, scientists have observed such discharges up close and found that they are triggered not by the grain itself, but by invisible visitors from space and from the ground.

A stream of scorching gas races away from a star, and suddenly stalls, as if it hit an invisible wall. That's exactly what researchers saw when they tried to reproduce a stellar eruption on a laboratory scale. They used a laser to create a plasma jet and shot it through a magnetic field — first weak, then strong, like that of many stars.

In a dense cloud of gas and dust where giant stars are born, the ALMA telescope has spotted something familiar. Four thin gas jets shoot out from the same region, each leaving behind a chain of bright knots, like a dashed line.

Near black holes and neutron stars, plasma churns like water in a boiling kettle. But this 'kettle' has no walls — only magnetic fields that twist and tear. At the tears, thin sheets form where magnetic field lines reconnect, giving particles a kick like a surfer catching a wave.

A gamma-ray burst is a brief but extremely powerful flash of light, born from the merger of neutron stars or the collapse of a massive star. Inside such a flash, plasma flows race at enormous speeds and collide with each other.

A doughnut-shaped magnetic trap holds plasma made of boron and hydrogen. Inside, the temperature rises above one hundred million degrees — hotter than the center of the Sun. At such heat, nuclei collide and fuse, releasing energy.

When water boils in a kettle, waves of steam ripple through the kitchen. A similar process happens in space, in plasma — gas so hot that electrons are stripped from atoms. Around black holes and neutron stars, this plasma isn't just hot: its particles zip around at nearly the speed of light.