Greenwald density limit

The Greenwald density limit is a rule in nuclear fusion experiments that restricts the amount of plasma—the hot, ionized gas—based on its density and the size of the device. Essentially, it sets a maximum density for the plasma to prevent instabilities and damage to the reactor. When plasma reaches this limit, it indicates an optimal balance where the fusion process can be most efficiently sustained without risking disruptions. This limit helps researchers operate fusion devices safely and effectively, guiding them to maintain plasma conditions that maximize energy output while avoiding detrimental effects.