By forming the filamentary structures observed on the smallest and largest scales, matter and energy can be compressed in space. But it is clear that energy can be compressed in time as well - the universe is filled with sudden, explosive releases of energy. One example that Alfvén was familiar with is the solar flare, the sudden release of energy on the sun’s surface, which generates the streams of particles that produce magnetic storms on earth.... Understanding the explosive release of energy was the key to the dynamics of the cosmos.

Again, Alfvén and his colleagues drew inspiration not from mathematical theory, but from their practical work in technology. In the late fifties, Alfvén and others at the Royal Institute had been called in by the Swedish Power company, ASEA, to solve an urgent problem. Most of Sweden’s electrical supply is generated by hydroelectric power in the north of the country, and is then transmitted over six hundred miles to the industrial south. ASEA found that it was cheaper to transform the alternating current to direct current for transmission with large mercury rectifiers. A rectifier allows a current to pass in only one direction, holding it back for the other half of the cycle, thus producing DC. But every so often a rectifier would explode, causing considerable damage.

Herlofson and Alfvén were consulted because the rectifier mechanism, consisting of a low-pressure mercury vapor cell, employs a current-carrying plasma. The team from the Royal Institute rapidly located the problem: the pressure of the mercury vapor in the rectifiers was too low. As a result, at high currents nearly all the electrons carried the electrical flow, creating an unstable situation in which the plasma started to slosh about within the rectifier.

....(At) high current something else happened. If the ions accidentally spilled out of a region, the electrons in the current would rush toward the ions with such momentum that their collision pushed the ions farther out of the region. This accelerated the electrons more, and so on. However, a few ions would break away and accelerate toward the electrons on the other side, pushing most of them back. An ever-widening tear in the plasma would open up, with electrons bunching up on one side and ions on the other. As the gap widened, fewer electrons could pass, so the current... would drop. This is like unplugging an appliance. The drop in current produces a sudden drop in the magnetic field created by the current, and the changing magnetic field creates a powerful electrical force that further accelerates the electrons. In the case of an unplugged appliance, the voltage becomes high enough to make a spark jump across from the socket to the plug. In the case of the rectifier, the voltage builds and builds until the electrons heat the rectifier plasma so hot that an explosion ensues, and gigantic sparks jump through the air in the station. Energy is suddenly released, creating the explosive damage.⁷³