回旋动理学是在磁化等离子体当中，带电粒子的轨迹是一个围绕磁力线的螺旋运动。它可以解耦为一个快速的回旋运动和和一个相对来说比较慢的导心运动。对于等体中的许多问题，只需要考虑后者就已经足够了。不论是传统的回旋平均，还是现在的李坐标变换，由于去除了不必要的回旋相位角这一维数，使得计算得到了简化。

Gyrokinetics is a theoretical framework to study plasma behavior on perpendicular spatial scales comparable to the gyroradius and frequencies much lower than the particle cyclotron frequencies. These particular scales have been experimentally shown to be appropriate for modeling plasma turbulence. The trajectory of charged particles in a magnetic field is a helix that winds around the field line. This trajectory can be decomposed into a relatively slow motion of the guiding center along the field line and a fast circular motion, called gyromotion. For most plasma behavior, this gyromotion is irrelevant. Averaging over this gyromotion reduces the equations to six dimensions (3 spatial, 2 velocity, and time) rather than the seven (3 spatial, 3 velocity, and time). Because of this simplification, gyrokinetics governs the evolution of charged rings with a guiding center position, instead of gyrating charged particles.