Solar Activity is Increasing, How to Protect Yourself from an EMP

Scientists are increasingly observing more and more sunspots on the Sun’s surface. This increase in space weather has the potential to cause electromagnetic pulses (EMP), or sudden bursts of electromagnetic (EM) energy, leading to major disruptions here on Earth.

Increasing Solar Activity

Space weather is an all-encompassing term for the variations in the space environment between the Sun and the Earth that can affect technology. Scientists forecast it by observing the number of sunspots, or dark areas on the solar surface, which indicate concentrated magnetic activity. Figure 1 shows sunspots on Sept. 16, 2024.The more sunspots there are, the more active the Sun is. Sunspots can lead to several types of natural EMPs. They include solar flares, an intense burst of high-energy radiation coming from the surface of the Sun, and coronal mass ejections (CMEs), large explosions of plasma and magnetic field from the Sun’s corona.

Fig. 1. Image of the Sun from Sept. 16, 2024 (left). Sunspots reported on Sept. 16, 2024 (right).

Newsweek is reporting that the monthly average sunspot number in August 2024 was 215.5. This is the first time that the number has been over 200 since September 2001. This data indicates that a solar maximum is imminent, but scientists say they need more time to analyze the data.

Impacts of Solar Cycles

The sun’s solar activity is on an 11-year-long loop, during which magnetic activity fluctuates with a maximum and minimum. We are currently in Solar Cycle 25, seen in Figure 2, which started in December 2019. Click here to see the full progression.

Fig. 2. Solar Cycle 25 progression as of Sept. 2024. Courtesy: Space Weather Prediction Center, NOAA

During each solar cycle, the magnetic field of the Sun flips when it is near its maximum. Scientists measure cycles from one minimum to the next. During maximum activity, observers witness two to three CME’s each day and see 200 or more sunspots. At minimum, there is usually one CME each week and just a few sunspots if any.

Under normal conditions, Earth’s atmosphere functions as a protective shield. However, space weather events alter the density of the ionosphere, causing a surge of particles to stream toward Earth.

Great Halloween Solar Storm

Substantial solar storms can have major impacts here on Earth. One of the largest solar storms recorded is the Great Halloween Solar Storm that took place in Mid-October to early November 2003. The storm peaked October 28-29, generating one of the largest solar flares ever recorded, an X45. Scientists classify the strength of a solar flare based on their X-ray brightness. Figure 3 shows the scale with A-class being the smallest and X-class being the largest. The GOES-12 Soft X-ray Imager collected a sequence of X-ray images during the storm. Figure 4 shows these images.

Fig. 3. Intensity of solar flares based X-ray flux level and impacts on Earth.

The storm caused aurora sightings in uncommon places like California, Texas, and Florida in the United States and also in Australia, central Europe and even as far south as the Mediterranean Sea region.

The storm was also disastrous. Solar particles bombarded several satellites, killing the Japanese ADEOS-II, which launched just the year before. Increased levels of radiation forced astronauts on the International Space Station to take shelter. On Earth, airlines changed routes to avoid the Earth’s poles, and a drop in GPS accuracy affected users. On the Unites States’s east coast an already stressed power grid was under even more pressure, with the U.S. Geological Survey (USGS) saying it had to take unspecified measures to avoid a blackout. The USGS also says communication interference forced the Department of Defense to cancel a maritime mission.

USGS scientists are using data from the storm to make improvements to satellites, communication networks, and other vital infrastructure for when the next big storm arrives.

Protecting Equipment During an EMP

Solar flares and CMEs are among the natural sources of EMP, alongside lightning strikes and electrostatic discharges (ESDs). Artificial sources encompass both nuclear and non-nuclear weapons, such as electromagnetic bombs.

Electric fields from EMP events can couple to equipment through openings in the framework (such as slots, holes, and windows), communications networks, and power conductors, rendering systems useless. EMP hardening can protect against the effects of EMPs. Three ways to do this are by:

• Housing critical equipment in shielded cabinets and enclosures
• Having redundant systems in place
• Utilizing non-linear protection devices that provide surge protection

EMP Hardening: Shielding

Shielding minimizes the exposure of equipment or cables to EM fields while maintaining their intended functionality.

In August 2022, the U.S. Department of Homeland Security’s Science and Technology division released guidance on how to use shielding to maintain mission critical equipment during an EMP event. Agencies use the guidelines to evaluate existing equipment and protections, and to make decisions when buying new equipment or building new facilities. These standards are in alignment with MIL-STD-188-125-1 and -2.

The three suggested low-risk EMP shielding approaches include:

• EMP-protected equipment enclosures: Designers created these for portability, making them practical when you only need to protect a few pieces of equipment. Typically, you will find servers or a single distribution transformer in these enclosures. Also called Faraday cages, they are made out of conductive materials, like copper, aluminum, or steel. These materials conduct electricity and shield the interior from external fields.
• EMP-protected shelters: Shelters are typically larger than a cabinet or rack enclosure and are ideal for remote locations to reduce maintenance requirements. Users can fix or transport shelters. They house control and communications equipment, vulnerable spare parts, and HVAC equipment.
• EMP-protected rooms or buildings: Designers construct rooms or buildings with metallic shielding, conductive concrete shielding, or hybrid concrete/steel shielding. They can also retrofit existing structures with these materials or incorporate them into new construction plans.

You must also protect all points of entry. Ways to do this include shielded cables, gaskets/spring fingers, filters, and nonlinear protection devices.

Fig. 5. Different methods of EMP shielding

EMP Hardening: Redundancy

Redundancy, or having spares or backups, can provide equipment with a level of resilience against EMP effects. A ‘plan B’ is useful, but you must protect the backups themselves from EMP effects. Shield them or relocate them to areas less likely to be impacted.

EMP Hardening: Surge Protection

Surge protectors divert extra voltage to keep levels consistent and prevent damage to devices. These are crucial because EMPs can trigger power surges. The rating on each surge protector indicates how much energy it diverts. The higher the joule rating the more protection it provides.

During an EMP event, devices and cables have to be able withstand the peak-induced voltages and current. The National Coordination Center (NCC) advises using a lightning-rated surge protection device on power cords, antenna lines, and data cables. However, because EMP electroc fields can rise as quickly as 1 ns, surge protection devices built for lightning will fail, necessitating other surge protection methods. Figure 6 shows EMP-induced surges on different conductors.

Using power lines as an example, NCC says the best way to reduce this overshoot for EMP type pulses is by using a surge protection device followed by a low pass filter. The agency recommends metal oxide varistors as the best surge protector in this case, provided steps are taken to prevent them from overheating.

Fig. 6. EMP inducted surges on conductors from the National Coordination Center.

While analyzing power lines, consider double surge protection on critical external lines entering EMP-protected areas. This recommendation addresses the potential occurrence of a double EMP event. The first burst could take out the first surge protection device, leaving the equipment vulnerable in case of a second burst or nearby lightning strike. Redundancy can occur by connecting the primary surge protection device where the cable leaves the building and then connecting a secondary device to that cable immediately before it enters the EMP area.

You can also install surge protectors at both ends of an antenna, but you need to ground each one directly through a separate low inductance cable or wire.

Mitigating the Impacts of EMP

As technology improves, the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) is working to find a way to better communicate about impactful space weather events. Fig 7 shows the current scale for geomagnetic storms and their impacts. This scale focuses on the effects to spacecraft, operations, power grids, and other infrastructure.

Fig. 7. Space Weather Prediction Center Geomagnetic Storm Scale.

Now is the time to protect critical equipment from the potential dangers of an EMP and EMA is here to help. We have decades of experience in all aspects of EMP. We can use our software simulation tool, Ansys EMC Plus, to model EMP interactions. Additionally, we have developed source region codes for underground test research and system vulnerability assessment. EMA has experience and specialized codes for radiation transport calculations.

Along with analysis and design, our experience includes:

• Performing high altitude EMP (HEMP) coupling to tactical shelters and enclosures
• Supporting underground testing
• Performing ship hardening testing
• Validating modeling of photon response of cables and PC boards

Let the experts handle your EMP problems. Click here to contact EMA and get started.