Question: What is the name of the spiral caused by the rotation of the sun?
About the article "Aurora", section "Frequency of occurrence".

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The pioneer of studies of the rotation of the Galaxy and the formation of the spiral arms was Bertil Lindblad in 1925.
He realized that the idea of stars arranged permanently in a spiral shape was untenable.
Since the angular speed of rotation of the galactic disk varies with distance from the centre of the galaxy (via a standard solar system type of gravitational model), a radial arm (like a spoke) would quickly become curved as the galaxy rotates.
The arm would, after a few galactic rotations, become increasingly curved and wind around the galaxy ever tighter.
This is called the "winding problem".
Measurements in the late 1960s showed that the orbital velocity of stars in spiral galaxies with respect to their distance from the galactic center is indeed higher than expected from Newtonian dynamics but still cannot explain the stability of the spiral structure.
Since the 1960s, there have been two leading hypotheses or models for the spiral structures of galaxies:  Star formation caused by density waves in the galactic disk of the galaxy.
The SSPSF model – star formation caused by shock waves in the interstellar medium.
These different hypotheses do not have to be mutually exclusive, as they may explain different types of spiral arms. 
In geometry, the spiral of Theodorus (also called "square root spiral", "Einstein spiral" or "Pythagorean spiral") is a spiral composed of contiguous right triangles.
It was first constructed by Theodorus of Cyrene. 
Ballerina's skirt shape.
As the Sun rotates, its magnetic field twists into a Parker spiral,The spiral nature of the heliospheric magnetic field had been noted earlier by Hannes Alfvén, based on the structure of comet tails.
The influence of this spiral-shaped magnetic field on the interplanetary medium (solar wind) creates the largest structure in the Solar System, the heliospheric current sheet.
Parker's spiral magnetic field was divided in two by a current sheet, a mathematical model first developed in the early 1970s by Schatten.
It warps into a wavy spiral shape that has been likened to a ballerina's skirt.
Further dynamics have suggested that "The Sun with the heliosheet is like a bashful ballerina who is repeatedly trying to push her excessively high flaring skirt downward".
Unlike the familiar shape of the field from a bar magnet, the Sun's extended field is twisted into an arithmetic spiral by the magnetohydrodynamic influence of the solar wind.
The solar wind travels outward from the Sun at a uniform rate, but an individual jet of solar wind from a particular feature on the Sun's surface rotates with the solar rotation, making a spiral pattern in space.
Unlike the jet from a sprinkler, the solar wind is tied to the magnetic field by MHD effects, so that magnetic field lines are tied to the material in the jet and take on an arithmetic spiral shape.
The cause of the ballerina spiral shape has sometimes been called the "garden sprinkler effect" or "garden hose effect", because it is likened to a lawn sprinkler with nozzle that moves up and down while it spins.
The stream of water represents the Solar Wind.
The Parker spiral shape of the solar wind changes the shape of the Sun's magnetic field in the outer solar system: beyond about 10-20 astronomical units from the Sun, the magnetic field is nearly toroidal (pointed around the equator of the Sun) rather than poloidal (pointed from the North to the South pole, as in a bar magnet) or radial (pointed outward or inward, as might be expected from the flow of the solar wind if the Sun were not rotating).
The spiral shape also greatly amplifies the strength of the solar magnetic field in the outer solar system.
The Parker spiral may be responsible for the differential solar rotation, in which the Sun's poles rotate more slowly (about a 35-day rotation period) than the equator (about a 27-day rotation period).
The solar wind is guided by the Sun's magnetic field and hence largely emanates from the polar regions of the Sun; the induced spiral shape of the field causes a drag torque on the poles due to the magnetic tension force.
During solar maximum the entire magnetic field of the sun flips, thus alternating the polarity of the field every solar cycle.
The cause of the ballerina spiral shape has sometimes been called the "garden sprinkler effect" or "garden hose effect", and likened to holding a lawn sprinkler, and moving it in your hand vertically up and down, while your body rotates.
The stream of water represents the Solar Wind, and moves radially outwards at all times. 
MHD applies quite well to astrophysics since over 99% of baryonic matter content of the Universe is made up of plasma, including stars, the interplanetary medium (space between the planets), the interstellar medium (space between the stars), the intergalactic medium, nebulae and jets.
Many astrophysical systems are not in local thermal equilibrium, and therefore require an additional kinematic treatment to describe all the phenomena within the system (see Astrophysical plasma).
Sunspots are caused by the Sun's magnetic fields, as Joseph Larmor theorized in 1919.
The solar wind is also governed by MHD.
The differential solar rotation may be the long term effect of magnetic drag at the poles of the Sun, an MHD phenomenon due to the Parker spiral shape assumed by the extended magnetic field of the Sun.
Previously, theories describing the formation of the Sun and planets could not explain how the Sun has 99.87% of the mass, yet only 0.54% of the angular momentum in the solar system.
In a closed system such as the cloud of gas and dust from which the Sun was formed, mass and angular momentum are both conserved.
That conservation would imply that as the mass concentrated in the center of the cloud to form the Sun, it would spin up, much like a skater pulling their arms in.
The high speed of rotation predicted by early theories would have flung the proto-Sun apart before it could have formed.
However, magnetohydrodynamic effects transfer the Sun's angular momentum into the outer solar system, slowing its rotation.
Breakdown of ideal MHD (in the form of magnetic reconnection) is known to be the cause of solar flares, the largest explosions in the solar system.
The magnetic field in a solar active region over a sunspot can become quite stressed over time, storing energy that is released suddenly as a burst of motion, X-rays, and radiation when the main current sheet collapses, reconnecting the field. 
The Earth's rotation axis moves with respect to the fixed stars (inertial space); the components of this motion are precession and nutation.
The Earth's rotation axis also moves with respect to the Earth's crust; this is called polar motion.
Precession is a rotation of the Earth's rotation axis, caused primarily by external torques from the gravity of the Sun, Moon and other bodies.
The polar motion is primarily due to free core nutation and the Chandler wobble.
Over millions of years, the rotation is significantly slowed by gravitational interactions with the Moon; both rotational energy and angular momentum are being slowly transferred to the Moon: see tidal acceleration.
However some large scale events, such as the 2004 Indian Ocean earthquake, have caused the rotation to speed up by around 3 microseconds by affecting the Earth's moment of inertia.
Post-glacial rebound, ongoing since the last Ice age, is also changing the distribution of the Earth's mass thus affecting the moment of inertia of the Earth and, by the conservation of angular momentum, the Earth's rotation period.