- Magnetic Susceptibilities

Magnetic Susceptibilities

We have seen that an assembly of nuclear magnets in a steady magnetic field $H_{_{0}}$ absorbs power from a suitably applied RF field.

We know from basic E&M theory (macroscopic formulation of Maxwell's equations) that absorption is associated with the imaginary part of the susceptibility $\chi$. In our case, $\chi =\chi ^{'}+i\chi ^{''}$ is the complex nuclear magnetic susceptibility, where $\chi ^{'}$ is the real part and is associated with dispersion while $\chi ^{''}$ is the imaginary part and is associated with absorption.

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We will first derive the static (no transverse RF field) magnetic susceptibility $\chi _{_{0}}$.