Solar magnetic field

The Sun’s magnetic field is generated by motions of electrically conducting plasma and changes over the solar cycle. It shapes features including sunspots, prominences, and coronal loops.

Solar dynamo: The process by which motions in the Sun’s conducting plasma generate and sustain its magnetic field. Differential rotation and convection continually regenerate the field.
Sunspot: A dark, relatively cool region on the solar photosphere where concentrated magnetic fields inhibit convective heat transport. Sunspots are the most familiar visible concentrations of the solar magnetic field.
Magnetohydrodynamics: The study of electrically conducting fluids interacting with magnetic fields. It provides the physical framework for understanding magnetic fields embedded in solar plasma.
Solar cycle: The approximately 11-year variation in sunspot numbers and related measures of solar activity. The magnetic cycle drives the rise and fall of sunspot activity.
Solar magnetogram: An image showing the distribution and often the line-of-sight component of magnetic fields across the Sun. Magnetograms map field measurements rather than showing the magnetic field directly.
Magnetic reconnection: A process in which magnetic field lines rearrange and release stored magnetic energy in a conducting plasma. Reconnection converts stressed solar magnetic fields into flares and other energetic events.
Solar flare: A sudden release of magnetic energy in the Sun’s atmosphere, producing radiation across the electromagnetic spectrum. Flares occur when stressed solar magnetic fields rapidly release energy.
Solar plasma: The ionized gas that makes up most of the Sun and conducts electricity. The field is coupled to this moving, electrically conducting material.
Solar irradiance: The Sun’s radiant power received per unit area at a specified distance, including its variation over time. Changing magnetic features produce small but measurable variations in the Sun’s emitted energy.
Potential-field source-surface model: A model of the corona that assumes a current-free magnetic field below a spherical surface where the field becomes radial. It offers a simpler reconstruction than models that include electric currents.

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