Degaussing is the process of decreasing or eliminating an unwanted magnetic field. It is used in a variety of applications including data destruction, reducing electromagnetic interference, and reducing magnetic signatures of ships. Degaussing accomplishes these goals by applying a reversing magnetic field that cancels out the existing field.
What is degaussing?
Degaussing is the process of decreasing or eliminating an unwanted magnetic field. It involves applying an alternating magnetic field that steadily decreases in intensity over time. This alternating field essentially cancels out the effects of the unwanted field. Degaussing can be applied to eliminate residual magnetism in ferromagnetic materials.
The term “degauss” refers to removing or canceling out magnetization. It comes from the last name of Carl Friedrich Gauss, a mathematician and physicist who made major contributions to understanding magnetism and electromagnetic theory in the 1800s.
How does degaussing work?
Degaussing relies on the principles of magnetic field cancelation. When two magnetic fields encounter each other, their effects can be lessened or negated completely depending on the strength and orientation of the fields. Degaussing equipment generates an alternating magnetic field that steadily decreases in strength over time.
As this degaussing field is applied to a magnetized object, the alternating field gradually cancels out the existing magnetic field in the object. The decreasing intensity of the degaussing field ensures that by the end of the process, no excess magnetization remains in the object.
Degaussing effectively randomizes the magnetic domains in ferromagnetic materials. It disrupts the alignment of electron spins that create the magnetic field, leaving materials with no net magnetic signature.
What is degaussing used for?
There are three main applications of degaussing:
- Data destruction – Degaussing is an effective way to completely erase data from magnetic storage media like hard disk drives.
- Reducing electromagnetic interference (EMI) – Degaussing electric motors, power transformers, and ballasts can help minimize electromagnetic noise.
- Reducing magnetic signatures – Naval ships are degaussed to minimize their magnetic signatures and avoid triggering naval mines.
In addition, degaussing can be used to demagnetize tools, erase magnetic tape and videotapes, neutralize magnetic fields from everyday objects, and calibrate magnetic sensors.
Data destruction
One of the most common uses of degaussing is to erase data stored on hard disk drives (HDDs) and magnetic tapes. These storage devices record data using magnetic charges on a ferromagnetic platter or tape. Degaussing these materials effectively scrambles the recorded data, rendering it unrecoverable.
Degaussing provides a way to completely destroy sensitive data like personally identifiable information, financial records, classified government documents, and more. It provides a more secure data destruction method compared to simply deleting files or reformatting drives.
Standards like the DoD 5220.22-M require degaussing to securely erase sensitive military and government data. Industries like healthcare, financial services, and defense rely on degaussing to make sure deleted files cannot be recovered.
Reducing EMI
Alternating current flowing through equipment like electric motors, ballasts, and transformers can produce electromagnetic noise known as electromagnetic interference (EMI). This radiated noise can interfere with radio, video, and other sensitive electronics. Degaussing these pieces of equipment can effectively reduce EMI.
EMI reduction is especially important in electronics manufacturing, aviation, hospitals, and other facilities operating sensitive electronics. Degaussing electric motors in manufacturing facilities can significantly cut down on electromagnetic noise pollution.
Reducing magnetic signatures
Naval ships contain a large amount of ferromagnetic material like steel that distorts and concentrates Earth’s magnetic field around the vessel. This magnetic signature can prematurely detonate naval mines and make ships susceptible to magnetic-fuze torpedoes.
Running electrical current through coils around the entire ship essentially cancels out this detectable magnetic signature. This process is known as deperming. Deperming combined with other degaussing systems can reduce a naval ship’s magnetic field to near zero and minimize its vulnerability.
Degaussing methods and equipment
There are a few common techniques and types of equipment used to degauss materials:
- Coil degaussing – Objects are passed through a coil loop energized with alternating current to create a decaying alternating magnetic field.
- Handheld bulk degaussers – Portable devices that can be manually applied to erase hard drives and other small media.
- Free-rotation degaussers – Motors spin storage media while exposing it to a degaussing field.
- Conveyor degaussers – Degauss hard drives and tapes continuously as they move through on a conveyor belt.
- Wanding – Using a handheld degaussing wand on a grid pattern over equipment.
- Deperming – Running electrical cables around a ship’s exterior to induce a degaussing field.
The optimal degaussing method depends on the size and type of object being degaussed. Smaller computer hard drives may be degaussed using a bulk handheld degausser or free-rotation degausser. Large power transformers and electric motors can be degaussed through coil loops or wanded on-site. And entire naval vessels are degaussed using carefully orchestrated deperming procedures.
Coil Degaussing
Coil degaussing involves moving magnetized objects through a coil of wire connected to an alternating current power source. As current cycles through the coil, it generates a decaying alternating magnetic field within the coil loop. This field effectively cancels out any persistent magnetic fields in the objects passing through the center.
Small coil degaussers are commonly used to erase hard disk drives, magnetic tape reels, and other magnetic storage media. The storage media is passed through the coil in different orientations until any residual magnetism is canceled out. Larger coil systems may be used to degauss larger equipment like motors or ballasts, by physically moving the equipment through the coil loop.
Handheld Bulk Degaussers
Handheld bulk degaussers are portable devices designed specifically to degauss hard drives and small magnetic storage tapes. These battery-powered units generate an alternating magnetic field from a coil inside the device. This field can be applied directly to hard drives and other media by pressing the degausser against the object.
For optimal data destruction, the degausser may need to be applied in multiple orientations to erase data from different parts of the drive. Handheld models offer a simple degaussing solution without needing large coil systems and give users more control over the degaussing process.
Free-Rotation Degaussers
Free-rotation degaussers use electric motors to continuously rotate hard drives or magnetic tapes while degaussing. The media rotations within a chamber surrounded by magnetic field generating coils. The degaussing field is applied from multiple angles as the media spins to ensure complete erasure.
The constant motion allows for quick and effective degaussing. But the automated rotation gives users less control than handheld application. Free-rotation degaussers provide efficient data destruction for large volumes of magnetic media.
Conveyor Degaussers
Conveyor degaussers use a moving conveyor belt to transport magnetic tapes, hard drives, and other media through a degaussing field. Items move through on the belt between two coils energized to generate a strong alternating field envelope. This continuously degausses large volumes of media with minimal handling.
Conveyor systems like tunnel degaussers offer an automated degaussing solution to erase materials as they move through. They allow degaussing at scale for data centers, institutions, and industries needing high-volume media destruction.
Wanding
Wanding uses a handheld magnetic wand manually passed over equipment to degauss it. The portable wands contain an electrical coil energized to induce a localized alternating field from the tip of the device. Slowly wiping the wand tip above a grid pattern over the equipment surface demagnetizes the material below.
Wanding provides a degaussing option for large electric motors, generators, ballasts, and transformers that cannot fit inside a coil. It allows for targeted degaussing of specific components that may be producing undesirable EMI levels.
Deperming
Deperming is the process of degaussing entire naval vessels while they are docked. It reduces the magnetic field distortions caused by the ship structure and onboard electronics. Ship degaussing systems called coiling involve running cables around a ship and powering them to induce an alternating cancelling field.
Advanced systems carefully adjust electrical current through different sections of coiling to optimize the degaussing effect. Deperming procedures are tuned to minimize the resultant magnetic signature from the vessel. This signature reduction is critical to avoid detonating magnetically-triggered sea mines.
Benefits of degaussing
Here are some of the major advantages and applications of degaussing technology:
- Data destruction – Degaussing provides secure erasure of sensitive information stored on magnetic media.
- Reusable media – Degaussed magnetic tapes and disks can be reused unlike with physical destruction.
- No hazardous materials – Degaussing is an environmentally friendly process with no hazardous waste.
- EMI reduction – Degaussing electric equipment reduces radiated electromagnetic interference.
- Military naval protection – Deperming minimizes magnetic signatures from ships helping avoid sea mine detonation.
- Demagnetization – Degaussing neutralizes magnetic fields and permits accurate magnetic sensor calibration.
Degaussing provides a convenient and reliable way to safely minimize unwanted magnetization from objects and equipment. It is a core component of physical data destruction procedures. Degaussing also supports electromagnetic compatibility by attenuating interference from motors, generators, transformers and ballasts.
Limitations of degaussing
While degaussing is useful in many applications, it does have some limitations:
- Cannot directly degauss equipment that is not ferromagnetic like solid state drives.
- May not degauss magnetic media 100% if procedure is not performed properly.
- Not effective for erasing extremely high-density storage like cassettes and floppy disks.
- Portable degaussers have weaker fields suited only for smaller objects.
- Does not physically destroy media, allowing for possible remagnetization.
- Repeated deperming can weaken ship hulls and requires drydocking ships.
- Only reduces EMI rather than eliminating electrical noise sources.
Degaussing procedures must be carefully controlled to completely purge magnetic signatures. Certain dense media may require physical destruction to guarantee data removal. And degaussing alone does not address root causes of electromagnetic interference.
Is degaussing permanent?
A properly executed degaussing process will permanently erase magnetic data storage media and disrupt any magnetization in materials. However, it is possible to re-magnetize degaussed media under certain circumstances.
Degaussed hard disk drives, tapes, and disks have randomized magnetic domains with no usable signal. But reintroducing a strong magnetic field can partially realign these domains and make data recovery possible again. While unlikely, this illustrates degaussing alone does not necessarily result in a permanent physical change.
To prevent any chance of remagnetizing degaussed media, many organizations follow up with physical destruction procedures like disk shredding or data wiping. Degaussing combined with mechanical destruction offers a layered data sanitization approach.
For applications like EMI reduction, items may gradually become re-magnetized over time after degaussing. Periodic re-degaussing helps maintain low electromagnetic interference levels.
Is degaussing secure data destruction?
Degaussing is an approved method for securely destroying sensitive data stored on magnetic media. Standards like the DoD 5220.22-M and NIST 800-88 include degaussing as an acceptable sanitization method.
However, degaussing by itself is generally not sufficient for high security applications. Various government and industry standards layer degaussing with other processes like physical destruction or data wiping. This ensures magnetic data is irrecoverable.
High-security degaussing requires validation testing to verify media was properly degaussed. Handheld degaussers also require trained operators to guarantee consistent results. Automated degaussing systems with conveyors provide more reliable high-volume data sanitization.
While degaussing can often fully erase data beyond recovery, pairing it with physical destruction gives maximum assurance when completely eliminating sensitive information.
Alternatives to degaussing
Here are some common alternatives to degaussing:
- Data wiping – Overwriting magnetic media with non-sensitive data to replace sensitive files.
- Encryption – Encrypting data can make it unreadable without proper decryption keys.
- Physical destruction – Physically demolishing media through methods like shredding and incineration.
- Strong magnets – Can scramble data similar to degaussing but less controlled process.
Data wiping overwrites existing data to obscure it but can leave recoverable remnants. Encryption scrambles data into unreadable ciphertext. Physical destruction utterly destroys media but prevents reuse.
For quickly sanitizing magnetic media and reducing EMI, degaussing provides a reliable process combining data destruction effectiveness, information security, and efficiency. But for maximal data security, pairing degaussing with encryption or physical methods is recommended.
Conclusion
Degaussing is a vital magnetic data destruction and electromagnetic noise mitigation tool with a variety of applications. It offers a way to safely and efficiently purge magnetically recorded data and minimize EMI from equipment.
Though degaussing has some limitations, proper procedures can securely erase magnetic media for reuse. Combining degaussing sanitization with complementary processes like physical destruction and encryption provides maximum security and permanence for data removal.
Understanding the principles, equipment, procedures, and limitations for degaussing enables its effective use across data-sensitive industries including healthcare, finance, aerospace, and military.