alfven wave

A ring-shaped channel of gallium arsenide is like a round pool with no rim: electrons flow in through the inner bank and out through the outer one. In an ultraclean material, they collide with each other more often than with lattice defects, and they begin to behave like a fluid.

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.

The solar wind is a stream of charged particles constantly blown off the Sun's surface, filling the entire solar system. It's not like a steady breeze: it has eddies, gusts, and calm patches. Scientists call this turbulence.

In the solar corona, it rains from time to time — only not water, but plasma. The hot gas cools, clumps into blobs, and rushes downward along magnetic loops, like drops running down invisible gutters.

The solar corona is the Sun's outer atmosphere, heated to millions of degrees. How it gets so hot is still unclear. One candidate is torsional waves: they twist magnetic field lines like a rubber band. Such waves were recently spotted with the new Daniel K. Inouye Solar Telescope.

The solar corona lives its own turbulent life. Magnetic fields here are governed by the motions of the dense surface — the Sun's photosphere — but occasionally they rewrite the magnetic pattern themselves.

At the center of a distant galaxy, where a supermassive black hole weighing a hundred million suns spins, space is threaded with magnetic fields. They coil into tight vortices, like a drain in a sink, but instead of water, there's plasma whipped up to near-light speeds.

The flash lasts a thousandth of a second, but in that instant it releases as much energy as the Sun emits in a day. Such signals, fast radio bursts, have been caught by telescopes since 2007, and their source remains a mystery. A new study offers an elegant answer: it's all about a cosmic amplifier.

The solar wind rushes from the Sun to Earth, but the magnetosphere bends the flow and sculpts it into plasma tails. The same motif plays out at the heart of galaxies: jets from accretion disks around black holes are twisted by the invisible hand of a magnetic field.

Light from a distant blazar, an active galactic nucleus whose jet points our way, travels for billions of years. Along the way, it triggers cascades of charged particles that the intergalactic magnetic field deflects sideways. This creates a blurred gamma-ray glow around the blazar: a secondary halo.

A lighthouse sends its beam through a storm of its own mirrors: that's roughly how fast radio bursts behave when trying to leave a magnetar's vicinity. A magnetar is a neutron star with a magnetic field a quadrillion times stronger than Earth's.

Red giants are swollen, aging stars. Deep inside, an ocean of plasma churns: heat forces its way from the core to the surface, generating waves like a mighty surf. The star's magnetic field acts like an invisible seabed – it steers these waves, changing their height and speed.

The paradox of the young solar wind has long puzzled heliophysicists. Measurements showed that near the Sun, proton beams aren’t smeared out but sharply compressed, as if someone had neatly hammered them into the shape of a hammerhead.

The Sun is a boiling cauldron of hydrogen and helium, where scorching gas is caught in magnetic snares. When invisible ropes reconnect, energy comparable to billions of thermonuclear explosions is released. Where does it go?

In December 2011, Comet Lovejoy boldly raced through the searing corona of the Sun. Right after — a flare. Scientists checked whether the comet could have caused it. The atmosphere of the Sun is threaded with taut magnetic loops, like a drawn bowstring.

A thick rubber band is twisted tighter and tighter. At some point, it can't take it anymore — it snaps and whips around, releasing the stored energy. That's roughly how magnetic fields inside neutron stars — the ultra-dense remnants of exploded stars — behave.

The crown of a huge tree sways in the wind, but the roots and trunk are hidden underground. On the Sun, magnetic fields play the role of such invisible roots. They emerge from the depths, thread through the entire atmosphere, and govern the motion of the hot gas — plasma.

Layers of a thin material rotated relative to each other resemble stacked grids. Where the lines intersect, a new pattern emerges — a moiré. In this pattern, electrons move differently than in a regular crystal and can form unexpected states. In the new study, researchers took two layers of molybdenum telluride and twisted them by 4.8 degrees.

Two neutron stars spiral closer together, about to merge in an instant. Their dance lasts fractions of a second, but just before the finale, one star plows into the other's magnetic envelope, like a swimmer cutting through water, kicking up waves. At that moment, a complex system of currents is born, carrying energy away.

A superfluid gas behaves like a frictionless liquid. Two clouds of such gas are connected by a narrow bridge, and a stream of particles flows through it. This resembles the Josephson effect in superconductors, but here the particles are neutral atoms instead of electrons.

A radio signal travels from Mars to Earth, but on the way it has to push through the invisible "wind" of charged particles blowing from the Sun. This wind, like ripples on water, slightly distorts radio waves.

The solar wind isn't a smooth flow: it's gusty. Inside it, protons and helium nuclei don't all travel at the same speed; they spread out like droplets in a hose stream. Usually, this spread is described by a simple bell-shaped curve.

In a disk of gas and dust around a young star, dust particles behave like sand grains in a stream of water: the gas flows faster, the dust lags behind, and friction arises between them. This friction can rock the magnetic waves that run through the disk. The galaxy is full of such disks: it is precisely in them that planets are born.

A shock wave in the Sun's corona is like the sonic boom from an airplane, except instead of air there is scorching plasma, and instead of sound there is a jump in density and magnetic field. On March 10, 2024, such a wave swept across the western part of the solar disk.

In the dark cloud G351, where new stars are about to emerge from gas and dust, the magnetic field has bent into an hourglass shape. Such a shape is a sign that the field is not just watching star birth from the sidelines but is actively taking part. Scientists used the SOFIA telescope, mounted on an airplane, to see the dust in the cloud.

The Sun's corona looks like a shaggy dandelion: bright petal-like loops hold hot gas near the surface, while long, tenuous jets escape into space between them. These jets, the heliospheric current sheet, stretch across the entire solar system.

A neutron star is a city the size of a metropolis squeezed into a small asteroid. Around it, plasma, a gas of charged particles, seethes, and waves ripple through it like ripples on a pond. There are three kinds of waves: Alfvén (A), ordinary (O), and extraordinary (X).

A neutron star the size of a city spins faster than a kitchen blender, flinging particles around itself. A glowing cloud forms around it — called a pulsar halo. The shape of this cloud depends on invisible magnetic fields that, like ocean currents, steer the particles.

A solar flare is like a giant spring that gets twisted and twisted, and then suddenly snaps. The energy stored in the magnetic field is unleashed into space within minutes, heating plasma to millions of degrees.

Two aging spacecraft, launched back in 1977, are flying through interstellar space — the region where the Sun's influence fades. The Sun doesn't just shine; it continuously blows a stream of charged particles that forms a giant bubble around our system — the heliosphere.

The Parker Solar Probe and Solar Orbiter spacecraft fly close to the Sun and measure the solar wind — the stream of charged particles that constantly blows from our star.

Plasma is a gas heated so intensely that electrons are stripped from atoms. Waves run through it, akin to sound in air, but they are governed by the magnetic field. When the magnetic field becomes periodic rather than uniform, like a fence with alternating slats, waves behave differently. Some frequencies simply vanish: the wave cannot propagate and is reflected back.

In a pot of boiling soup, small bubbles churn, but gradually large-scale flows come to dominate. Something similar happens in cosmic plasma, where magnetic fields behave like tangled threads.

A fusion reactor is an attempt to hold a miniature sun in a magnetic cage. To get more energy out of it, you need to squeeze the plasma denser. But tokamaks have an invisible fence: once the density crosses a certain line, the plasma shudders and falls apart. This disruption is one of the main mysteries on the road to clean energy.

The Sun constantly emits a stream of charged particles, mostly hydrogen — the solar wind. Sometimes the Sun ejects dense blobs of magnetized gas, inside which calm usually reigns. But in 2000, scientists noticed two regions inside one such cloud where the gas was churning.

In a conventional superconductor, electrons team up into pairs that stay put: their total momentum is zero. But sometimes it's different: pairs gain a shared momentum and start moving, like a school of fish swimming against the current. This state is called a pair density wave, and it's very finicky: it needs special conditions.

In a hot gas of charged particles — plasma — chaotic electric fields work like a sieve. A slow particle gets surrounded by a cloud of opposite charges, which cancels the external field. A fast one sheds this armor and gets accelerated.

Every hour, when the hands of a clock align at twelve, something happens in Earth's magnetosphere. It's as if an invisible conductor raises a baton, and waves race along magnetic field lines toward the surface. They're called pearls: on recordings, they look like a string of beads strung along time.

The solar wind isn't a calm stream but a bubbling soup of charged particles. Diving close to the Sun, the Parker probe picked up two types of stirring waves. Left-handed ones, like a whisk in a chef's hand, whip up the material when the temperature differs along and across the flow.

The muon is a tiny spinning top, twirling in the turbulent sea of the vacuum. Its magnetic axis points slightly away from what the Standard Model predicts. The deviation is just a couple of parts per million, but for physicists, it's a full-blown mystery. The vacuum is not a dead calm.