\begin{equation}
F_{m}=- \frac{3}{4}\frac {H_{c}{a}^{2}i_{u}\mu_{0}\left(2z+2z_{0}\right) V_{m}}{\left( {a}^{2}+{z}^{2}+2z z_{0}+{z_{0}}^{2} \right) ^{5/2}}%herausgehobener Bruch
\left( \underbrace{\frac {\it i_{u}a^2}{\left20(a^{2}+z^{2}+2z z_{0}+{z_{0}}^{2}\right)^{3/2}H_{c}}}_{<<1}+1 \right).
\label{eq:FmVereinfachung}
\end{equation}
\begin{equation}
F_{m}=- \frac{3}{4}\frac {H_{c}{a}^{2}i_{u}\mu_{0}\left(2z+2z_{0}\right) V_{m}}{\left( {a}^{2}+{z}^{2}+2z z_{0}+{z_{0}}^{2} \right) ^{5/2}}%herausgehobener Bruch
\left( \underbrace{\frac {\it i_{u}a^2}{\left(a^{2}+z^{2}+2z z_{0}+{z_{0}}^{2}\right)^{3/2}H_{c}}}_{<<1}+1 \right).
\label{eq:FmVereinfachung}
\end{equation}