The Bloch equation demonstration


The demonstration showed:
Precession:
The magnetization oscillate in the xy-plane
Radio waves are emitted

Resonant excitation (selective, soft pulse)
A weak resonant RF field will rotate the magnetization.
Only circularly component following precession contribute.

Non-selective excitation
A short strong RF pulse excites non-selectively

T2- and T1-relaxation

Rotating frames of reference
Often chosen to match the RF frequency
MR measurements are described in this frame
Measurement data are demodulated by this frequency

Software and animations with soundtracks:
http://www.drcmr.dk/bloch