The enigma of fast radio bursts (FRBs) is not just a question of 'what exploded?' It’s a drama of energy transfer under extreme conditions, where the slightest stumble leads to collapse. When Jocelyn Bell Burnell discovered pulsars, radio astronomy first heard the coherent cry of neutron stars. Today, FRBs break records; their sources are magnetars, born in the crucible of supernovae. In milliseconds they spew up to 10⁴² erg, and the brightness temperature soars to an unthinkable 10³⁷ K. Any theoretical model must convert the central engine’s energy into kinetic energy — accelerate particles nearly to the speed of light — and only then convert it into radio waves. It’s like a frantic relay race, where a red-hot baton is passed from the stellar core to electron bunches, and from them to radiation. But at every stage the race can stumble.

The physical constraints are simple and ruthless. The kinetic luminosity of a beam is tightly tied to its density, size, and Lorentz factor. For a radio burst to flare, particles must radiate as a single orchestra, but their solo time is negligible — about 10⁻¹³ s. Without continuous energy replenishment, the beam cools instantly: the radiation peak slides into the infrared, and the gigahertz signal fades. In other words, the runners on this track need not one-off spurts but a ceaseless tailwind — as if an invisible accelerator is strapped to each electron’s back, working without pause. Analysis of three model classes — from magnetospheric ones inside the light cylinder to scenarios with magnetic reconnection and a synchrotron maser on external shock waves — shows that such energy doping requires electric fields comparable to the magnetic field, and an extremely compact emission region.

Nature is particularly merciless with the popular synchrotron maser scenario on relativistic shock waves. Here, induced Compton scattering comes into play — an effect that turns the outgoing photon flux into an impenetrable cloud of mirrors. Photons that have not yet broken free begin to scatter off electrons and, instead of escaping, get stuck in a plasma labyrinth, heating it. The optical depth for typical parameters reaches τ ≈ 490, almost independent of the details. Only extreme magnetization $σ_w$ ≳ 30 can rescue the model, but then the overall efficiency shrinks to a pitiful 10⁻¹⁰. As Enrico Fermi wryly noted, 'accelerating particles is a delicate business,' and here it becomes a hopeless one. All 'long-range' models that transfer energy over astronomical distances without constant nudging hit a kinetic dead end.

Only scenarios in the death grip of a neutron star survive: either near its surface, or inside the light cylinder, where monstrous magnetic fields give rise to longitudinal electric fields that continuously spur particles on. This shifts the research focus to the physics of charge-starved gaps and coherent curvature radiation. Here, in the realm of superstrong fields, numerical simulations (PIC modeling) become the main tool, and FRBs themselves become unique probes for testing electromagnetism in regimes that on Earth last mere femtoseconds. No wonder Subrahmanyan Chandrasekhar called neutron stars 'stellar laboratories.' Solving the kinetic puzzle will not only explain the birth of the brightest flashes in the Universe, but perhaps allow us to create coherent radiation in compact plasma devices — or even build sources that can see through rock.