It’s a scene out of a science fiction movie: A nuclear detonation creates a burst of electromagnetic energy that wipes out communication and electronic equipment and disables the nation’s power grids. From the internet to cell phones, all systems fail. Chaos erupts as America is thrown back into the dark ages—all technology and critical infrastructure suddenly gone.
Could that actually happen? Los Alamos National Laboratory physicist Randy Bos says, “Probably not.”
Bos is a nuclear weapons effects specialist who has researched weapons effects for decades and has provided nuclear detonation response guidance for Federal Emergency Management Agency teams. “Yes, we know a nuclear explosion will generate an electromagnetic pulse (EMP), which, depending on the circumstances, could disrupt certain electronic equipment, but the doom and gloom scenarios will not happen. That stuff belongs in Hollywood,” he says.
Bos explains that researchers first discovered that nuclear weapons generate a burst of electromagnetic energy in 1962, when a high-altitude nuclear test, called Starfish Prime, detonated above the Pacific Ocean and hundreds of streetlights in Oahu, Hawaii, more than 700 miles away, went dark.
Nuclear explosions generate gamma rays that can react with air molecules, causing a powerful wave of electromagnetic energy—electric and magnetic fields traveling at the speed of light. Because of the way high-altitude denotations interact with the atmosphere and the Earth’s magnetic field, high-altitude EMPs can be especially destructive, having the potential for far-reaching effects on electrical and electronic systems. Bos notes that during nuclear detonations near or on the Earth’s surface, areas that would experience significant EMP effects would also be severely impacted by air blast, thermal radiation, and fire. “When you’re at ground zero of a near-surface detonation, EMP isn’t going to be the biggest concern.”
EMPs pose no threat to people, but they can cause dramatic voltage surges that may impact everything from car engines to cell phone transmitters. Bos says the key word here is “may.” The crippling devastation EMPs produce in the movies are highly unlikely, according to Bos.
“In general, the EMP must occur at the right place and the right orientation to have a significant impact,” Bos says. “There are multiple factors that must coincide.”
Bos notes that the U.S. national laboratories and other government agencies are working with industry experts to study and develop systems that can withstand all types of electromagnetic disturbances. A 2019 executive order prioritized research and development to address the potential danger of an EMP. Los Alamos scientists are supporting that order through projects that calculate EMP effects and electrical power grid performance.
Bos says scientists have digitized and analyzed EMP data from historical testing and EMP emulators—devices that mimic the output of an EMP. They’ve also used computer simulations to examine EMP impacts. Multiple government studies have examined the EMP threat, and private companies have researched how an EMP will affect telecommunications and power grids.
The risks of EMPs are similar to those of geomagnetic storms—naturally occurring disturbances in the space around the Earth controlled by the planet’s magnetic field. “The power industry has done a great deal of work to protect the nation’s electric grid from power surges and potential outages caused by geomagnetic storms,” says Bos, pointing out those measures also mitigate against a nuclear explosion–generated EMP.
“These technological advances and hardening measures help protect electrical production facilities, transformers, and power distribution lines,” Bos says. “There was a period of time in the development of electronics, the power grid, and communications technology when the EMP threat would have been greater, but now most of the equipment will not be affected. Some unlucky people may end up with fried electronics, but most of us, at the worst, will just have to reboot our computer or cell phone.” ★