(plural arithmetic spirals)
- (mathematics) A spiral that increases in distance from the point of origin at a constant rate.
- The Parker spiral is the shape of the Sun's magnetic field as it extends through the solar system. 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.
It is a spiral whose equation in polar coordinates is linear, which would thus, when quantized, yield an arithmetic progression.