Adiabatic pulses.

Abstract

Adiabatic pulses are sometimes considered to be mysterious and exotic entities which are difficult to understand, complex to generate and impractical to implement. This work is an attempt to bring familiarity and to fulfill the preliminary needs of anyone interested in learning more about this subject. The response of magnetization to stimuli produced by adiabatic pulses is analyzed using vector representations in a frequency modulated rotating frame. The first section deals with basic principles of amplitude and frequency modulated pulses and a vector representation in a second rotating frame is used to explain how the adiabatic condition can be satisfied. The subsequent section explains the principles of offset independent adiabaticity. These principles are then used to design optimal functions for the amplitude, frequency, and magnetic field gradient modulations for adiabatic inversion pulses. The last section considers some practical aspects for those who want to develop methodologies involving adiabatic pulses.