Let the following sphere represent a hydrogen atom/proton:
When an magnetic field is externally applied, protons respond by precessing around the direction of the magnetic field.
It is important to note that the speed or frequency of precession is directly proportional to:
1. The strength of the magnetic field (B)
- Weaker magnetic fields result in lower precession frequencies
- Stronger magnetic fields result in higher precession frequencies
2. The atom's gyromagnetic ratio (y), an intrinsic property of the particle of interest that describes how the particle responds to a magnetic field.
The precession speed is called the Larmor frequency (w) and is calculated by:
w = - y * B.
*For simplicity, future animations will show precession as a rotating sphere (left) or just as a vector that represents the magnetization direction of the hydrogen atoms.