A charged particle traversing a uniform magnetic field follows a helical path when its velocity possesses both parallel and perpendicular components relative to the field.
- The magnetic force, acting perpendicularly to the particle's velocity, induces circular motion within the plane orthogonal to the magnetic field.
- The velocity component aligned with the magnetic field dictates the particle's movement along the field's direction.
Consequently, the particle's trajectory is a spiral (helical) path, where the magnetic force supplies the centripetal force for the circular component, and the parallel velocity component propels the particle along the field's axis.