Magnetism is one of the universe’s fundamental forces. While most people interact with weak magnetic fields daily, such as those found in refrigerator doors or speakers, scientists and engineers have developed devices capable of generating forces exponentially stronger. The quest to create the strongest magnetic field on Earth involves pushing the limits of physics and engineering, resulting in record-breaking differences that depend entirely on how the magnetic field is generated and measured.
Understanding Magnetic Field Measurement
The strength of a magnetic field is quantified using specific units, primarily the Tesla (T) and the Gauss (G). The Tesla is the standard international unit for magnetic flux density, with one Tesla being equal to 10,000 Gauss. Earth’s natural magnetic field, which protects the planet from solar radiation, measures less than 0.0001 Tesla. A typical permanent magnet used to hold notes on a metal surface registers only about 0.01 Tesla. High-resolution medical imaging devices, such as an MRI machine, operate in the range of 1.5 to 3 Tesla, representing a significant technological leap in field strength.
The World Record for Peak Magnetic Strength
Pulsed magnetism generates the strongest man-made magnetic field on Earth. This method generates an immense magnetic field for only a fraction of a second, which allows the magnet to reach strengths that would instantly self-destruct a continuous device. The highest non-destructive magnetic field ever recorded was a pulse of 100.75 Tesla, achieved in 2012 by researchers at the Los Alamos National Laboratory.
This short burst of energy lasts for a mere fifteen milliseconds, but this duration is sufficient for researchers to conduct precise measurements. While even stronger “destructive” fields have been generated, reaching hundreds of Tesla, they render the magnet inoperable after a single use. This makes the 100.75 Tesla field the most powerful repeatable tool for scientific inquiry.
The Strongest Continuous and Permanent Magnets
When the requirement shifts from a momentary pulse to a sustained, steady operation, the maximum achievable magnetic field strength drops significantly. The record for the highest continuous magnetic field is currently held by a hybrid magnet at the Steady High Magnetic Field Facility in Hefei, China. This facility successfully produced a sustained field of 45.22 Tesla in 2022.
This hybrid design combines a superconducting magnet, which generates a stable background field, with a resistive insert magnet that uses immense electrical power to generate the rest of the field. Achieving this continuous strength is a major challenge because the high current in the resistive coils generates massive amounts of heat, requiring complex, energy-intensive cooling systems. The forces generated by a sustained 45 Tesla field are relentless, constantly stressing the materials of the magnet, which must operate without failure for hours.
The strongest magnets accessible for common commercial and consumer applications are permanent magnets made from Neodymium Iron Boron (NdFeB). These magnets are the most powerful permanent magnets available today. They typically produce magnetic field strengths between 1.0 and 1.4 Tesla at their surface. This strength, while dwarfed by laboratory records, is orders of magnitude greater than traditional ferrite magnets and makes them invaluable in small, powerful devices like hard drives and electric motors.
How Extreme Magnetic Fields Are Used
High-field magnets are indispensable for research into new materials, particularly for studying exotic states of matter and the behavior of electrons in confined spaces. Researchers use these powerful fields to investigate high-temperature superconductivity, where materials lose all electrical resistance at relatively high temperatures.
Extreme magnetic fields are used for magnetic confinement in experimental nuclear fusion reactors. The intense fields are necessary to contain and control the superheated plasma, which reaches temperatures hotter than the sun’s core, preventing it from touching the reactor walls. The development of high-field superconducting coils is pushing the capabilities of medical imaging, leading to higher-resolution and more detailed MRI scans for diagnostic purposes.