"Friendly" EMP generator to help protect electronics against electromagnetic attack

Sandia National Laboratories researcher Leonard Martínez connects a high-voltage-insulating line that circulates oil between a coaxial transmission line (white tube on the left) and the blue oil-filled transmission horn. of the EMES machine. (Credit: Sandia National Laboratories/Randy Montoya).

Electromagnetic pulse (EMP) weapons might be a staple of movies and video games, but they pose a very real threat. With just about every facet of modern society reliant on electronic devices, Sandia National Laboratories has developed a “friendly” EMP generator to make sure military and civilian equipment can withstand such potentially devastating bursts of electromagnetic energy.

First studied in earnest during the early US atomic weapon tests in the 1940s and ’50s, an EMP is one weapon of mass destruction that, fortunately, has yet to be used in war or by terrorists. The principle is that detonating a nuclear weapon high in the atmosphere can generate a massive burst of radio energy that can overload electricity grids, and electric and electronic circuits and burn them out.

Over the decades, a lot of research has gone into EMPs and it makes for very unpleasant reading. A single EMP attack against even a country the size of the United States would have a devastating effect. The explosion itself might not pose much danger to those below, but the EMP would damage or destroy phones, power grids, communications networks, computers, laptops, smart cards, vehicle electronics, fuel pumps, medical equipment, industrial robots, and just about anything else that has a microchip or even a slightly advanced electrical circuit.

Worse, large H-bombs aren’t needed to create the pulse. Using magnetic coils, it’s possible to produce EMP effects with tactical nuclear warheads or even conventional explosives that could be fabricated by non-nuclear nations or even non-state hostiles. Microwave devices can also generate similar effects and a large solar flare aimed at the Earth can produce the worst EMP effects of all.

The ElectroMagnetic Environment Simulator (EMES) recently installed at Sandia National Laboratories is designed to deliver variable energy pulses to provide engineers with a better understanding of how EMP damages circuits. As a matter of routine, military-grade equipment is shielded against EMPs, but most civilian equipment up to and including power grids aren’t similarly protected, so devices like Sandia’s EMES are very important in making sure that our bank accounts don’t vanish in a blast of electrons.

According to Sandia, EMES is made up of a “hippopotamus-sized” Marx generator that generates a high-energy pulse from a low-energy DC power source, allowing it to simulate lightning and run high-energy physics experiments. EMES is connected to a large capacitor bank that provides a high-voltage blast every 15 minutes, creating the EMP effect. Meanwhile, absorbers behind the target zone soak up any stray energy from the pulse.

The EMES can produce its pulses within a microsecond of a command. This allows the research team to not just test the hardiness of a device against an EMP, they can also see how the pulse affects the device at any particular moment as it carries out its functions. This will help engineers in building stronger, more sophisticated safeguards.

In addition, the EMES can test a large number of components in a single session as one device can quickly be replaced by another as the generator recharges. If a device passes the EMES tests, it can then be sent on for testing against more aggressive EMP threats and its design improved incrementally.

“The builders or owners generally solicit help from my group when it comes to additional shielding designs,” says Leonard Martínez, the Sandia researcher in charge of the timing and firing control system. “The design focus can range from protecting tiny electronic parts to shielding larger subsystems of military equipment. Our customers may decide to implement additional shielding to their device in between tests, or even take the device back to their lab to design and add additional shielding. Then they would bring it back for retesting.”

EMES is located in a renovated test facility that operated earlier versions of the pulse-producing machine from 1978 to 1994, and was rekindled in the wake of the 9/11 terrorist attacks. In addition to testing both military and civilian devices, researchers at Sandia are looking to integrate the machine into a national testing center that would focus on improving the resilience of the national electricity grid.

Source: Sandia National Laboratories

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