All articles starting with M

Magnetic particle imaging

Magnetic particle imaging (MPI) is a radiation-free tomographic method that images iron oxide nanoparticle tracers in the body, reported by Gleich and Weizenecker in 2005.

Magnetic particle inspection, also called magnetic particle testing, is a nondestructive testing method that finds surface cracks in ferromagnetic materials by attracting particles to leaking magnetic flux.

Oct 22, 2026

Magnetic plasmon

A magnetic plasmon is a collective oscillation of conduction electrons in a metallic nanostructure that produces a resonant magnetic response, occurring in horseshoe-shaped nanostructures much smaller than the optical wavelength.

Magnetic pressure

Magnetic pressure is the pressure a magnetic field exerts perpendicular to its field lines on a conducting medium or plasma, equal to B²/(2μ₀) in SI units.

Oct 22, 2026

Magnetic proximity effect

The magnetic proximity effect induces a magnetic moment in a nonmagnetic material, such as Pt, placed in contact with a magnetically ordered material, decaying away from the interface.

Magnetic pulse welding

Magnetic pulse welding (MPW) is a solid-state joining process that uses a pulsed electromagnetic force to accelerate one workpiece into another, mainly for tubular lap joints.

Magnetic quantum number

The magnetic quantum number, ml, gives the projection of an electron's orbital angular momentum along an axis, usually a magnetic field, and splits spectral lines in the Zeeman effect.

Magnetic reconnection

Magnetic reconnection, also called magnetic merging, is a plasma process in which magnetic field lines break and rearrange, converting magnetic energy into particle energy and powering solar flares and auroras.

Magnetic refrigeration

Magnetic refrigeration is a cooling technology that pumps heat by cyclically magnetizing and demagnetizing a solid, exploiting the magnetocaloric effect instead of refrigerant gases; prototypes exist, but no mass-market product was available as of 2020.

Magnetic refrigerator

A magnetic refrigerator is a cooling device that pumps heat by magnetizing and demagnetizing a magnetocaloric material instead of compressing refrigerant gas, offering a refrigerant-free alternative to vapor compression.

Magnetic reluctance

Magnetic reluctance, also called magnetic resistance, is the opposition a magnetic circuit offers to magnetic flux, defined as magnetomotive force divided by flux and measured in ampere-turns per weber.

Magnetic resonance angiography

Magnetic resonance angiography, or MR angiography, is a set of MRI techniques that visualize blood vessels and blood flow, often without injected contrast or ionizing radiation.

Magnetic resonance cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive MRI technique, first described in 1991, that images the bile ducts, gallbladder, and pancreatic duct without radiation or contrast, serving as the noninvasive alternative to diagnostic ERCP.

Magnetic resonance elastography

Magnetic resonance elastography is an MRI technique that measures soft tissue stiffness by imaging shear waves, used mainly to detect and stage liver fibrosis and reduce the need for liver biopsy.

Magnetic resonance fingerprinting

Magnetic resonance fingerprinting is a quantitative MRI technique, introduced at Case Western Reserve University in Nature in 2013, that measures several tissue properties simultaneously from one scan.

Magnetic resonance force microscopy

Magnetic resonance force microscopy (MRFM) is a scanning probe technique that detects magnetic resonance signals from spins by measuring the mechanical force they exert on a magnet-tipped resonator.

Magnetic resonance imaging

Magnetic resonance imaging (MRI), also once called NMRI, is a medical imaging method using strong magnetic fields and radio waves, founded on Lauterbur's 1973 gradient-encoding work and Mansfield's fast imaging, honored by the 2003 Nobel Prize; it images soft tissue without ionizing radiation.

Magnetic resonance imaging of the brain

Brain MRI (head MRI) images the brain using a strong magnet, radio waves, and a computer without ionizing radiation. Field strengths of 1.5, 3, and 7 tesla; gadolinium contrast; used for stroke, tumors, and multiple sclerosis.

Oct 21, 2026

Magnetic Resonance Myelography

Magnetic resonance myelography (MRM) is a heavily T2-weighted MRI sequence showing CSF, the thecal sac, and nerve roots, used for spinal stenosis and CSF leak work-up, with or without intrathecal gadolinium.

Magnetic resonance neurography

Magnetic resonance neurography (MRN) is an MRI technique that images peripheral nerves directly, used to diagnose entrapment neuropathies, traumatic nerve injury, plexus disorders, and nerve sheath tumors.

Magnetic resonance spectroscopic imaging

Magnetic resonance spectroscopic imaging, also called chemical shift imaging, is an MRI technique that maps metabolites across the brain, used to characterize tumors and epileptic foci.

Magnetic resonance urography

Magnetic resonance urography (MRU) is an MRI technique that images the kidneys, ureters, and bladder without ionizing radiation, used to diagnose obstruction, congenital anomalies, and tumors.

Magnetic resonance velocimetry

Magnetic resonance velocimetry, also known as flow MRI or phase contrast MRI velocimetry, is an MRI technique that measures three-component velocity fields of fluids, including flows inside opaque geometries that optical methods cannot reach.

Magnetic Reynolds number

The magnetic Reynolds number, usually written Rm, is a dimensionless number comparing magnetic field advection to diffusion in a conducting fluid; above a critical value, self-sustaining dynamo action occurs.

Magnetic rotation

Magnetic rotation is a mode of nuclear excitation in which rotational-like gamma-ray sequences arise from closing proton and neutron angular-momentum blades, producing shears bands dominated by magnetic dipole radiation.

Magnetic sail

A magnetic sail, or magsail, is a proposed propellantless spacecraft propulsion system that deflects solar wind plasma with a superconducting loop; Andrews and Zubrin proposed it in 1988.

Magnetic scalar potential

The magnetic scalar potential is a scalar function whose negative gradient gives the magnetic field in current-free regions, obeying Laplace's equation and used to model Earth's magnetic field.

Magnetic shear

Magnetic shear is a measure in magnetic confinement fusion of how quickly the safety factor changes across the plasma, making it an alternative description of the current profile.