The most studied stellar magnetic field

The Sun, the only star our solar system, has show that it has a magnetic
field that reaches all over its surface. Astronomers know that this
magnetic field affects the rotation of the Sun and the movement of chemical
elements around its surface. It has concentrated areas of magnetism
called sunspots (dark areas on the Sun that produce magnetic storms).
While astronomers remain uncertain of exactly how the Sun’s magnetic
fields work, the most widely accepted theory involves a stellar dynamo.
A stellar dynamo can be thought of like a generator (an engine
usually fueled by gas that spins a magnet wrapped in coil, producing electricity).
Astronomers theorize that in the case of the Sun, instead of producing
electricity, the stellar dynamo generates a magnetic field in two
ways, each involving powerful motions. The first involves the movement
of gases in the convection zone. (A convection zone is the upper layer of
a star.) In this zone, material close to the surface of a star rises as heat
moves outward from the lower layers of the surface. This process results
in hot gas rising from the surface, in a way that is similar to hot air rising
on Earth. Upon the release of the heat of the gas at the Sun’s surface,
the gas drops down again as it replaced by the hotter gases below the surface.
The second type of motion in a stellar dynamo is a result of the Sun
being made of gas (mainly hydrogen and helium). When the Sun rotates,
its speed is varied due to its gassy composition; this differs from planets,
whose solid composition produces a regular rotation. The irregular rotation
of the Sun is called differential rotation. It causes the equator (the
middle of the Sun) to spin faster than the poles (the top and bottom of
the Sun).