\documentclass[crop,border=5,tikz,convert={outext=,
command=\unexpanded{pdf2svg \infile\space\outfile\%02d.svg
all}},multi=false]{standalone}
\usetikzlibrary{math,calc,through,shapes,patterns,decorations.pathmorphing}
\usepackage{tikz-3dplot}
\tdplotsetmaincoords{70}{120}
\begin{document}
\begin{tikzpicture}[>=latex,scale=1,tdplot_main_coords]
\coordinate (A) at (-1,0,1);
\coordinate (B) at (1,0,1);
\def\myscale{1}
\foreach \x in {-1,0,1}{
\foreach \y in {-1,0,1}{
\draw[thick,black!50!blue](\myscale*\x,-1.5,\myscale*\y+1)--(\myscale*\x,1.5,\myscale*\y+1);
\draw[black!50!blue,->](\myscale*\x,1,\myscale*\y+1)--(\myscale*\x,0.05,\myscale*\y+1);
}
}
\node[black!50!blue] at (0,-1.8,1.1) {$\vec{B}$};
\draw[ultra thick,->,draw=black!50!green] (0,0,1)--(0,0,-0.9);
\node[anchor=west,black!50!green] at (0,-0.7,-1){$\vec{F}_{\mathrm{m}}$};
\draw[ultra thick,black] (-1,0,3.8)--(A)--(B)--(1,0,3.8);
\draw[<->,black] ($(A)+(0,0,2.5)$)--($(B)+(0,0,2.5)$)
node[midway,above]{$b$};
\draw[ultra thick,->,black] (B)--+(0,0,2.5) node[left]{$I$};
\draw[ultra thick,->,black] (A)--+(1,0,0);
\draw[ultra thick,->,black] (-1,0,3.5)--+(0,0,-0.5);
\end{tikzpicture}
\end{document}