magnetic field with 2 coils

Question

I want to draw a magnetic field lines between 2 coils, like this picture (hand-drawn :-).

Is it possibile to draw it using, e.g., "a combination" of CircuiTikz, pst-magneticfield...? Any idea? Any suggestions?

Answer 1

Something like this?

It's made in 3d, with a macro for the coils, and it needs layers to fix the visibility and a couple of tikz styles (arrows, and borders in some lines).

\documentclass[border=2mm]{standalone}
\usepackage    {tikz}
\usetikzlibrary{3d}
\usetikzlibrary{decorations.markings}
% isometric perspective
\pgfmathsetmacro\xx{1/sqrt(2)}
\pgfmathsetmacro\xy{1/sqrt(6)}
\pgfmathsetmacro\zz{sqrt(2/3)}
% layers
\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers   {background,main,foreground}
% coil
\newcommand\mycoil[3] % position (center of the bottom coil), number of turns, terninals (-1/left, 1/right)
{%
  \begin{scope}[shift={#1},x={(-#3\xx cm,-\xy cm)},y={(#3\xx cm,-\xy cm)}]

    \foreach\i in {0,...,#2}
    {%

      \begin{pgfonlayer}{background}
        \draw plot[variable=\x,domain=0.5:1,samples=40,smooth]
          ({0.5sin(360\x-45)},{0.5cos(360\x-45)},{0.4(\x+\i)});
      \end{pgfonlayer}
      \begin{pgfonlayer}{foreground}
        \draw[preaction={draw,white,line width=2pt}] plot[variable=\x,domain=0:0.5,samples=40,smooth]
          ({0.5sin(360\x-45)},{0.5cos(360\x-45)},{0.4(\x+\i)});
      \end{pgfonlayer}
    }
    \pgfmathtruncatemacro\h{#2+1} % coil height
    \begin{pgfonlayer}{foreground}
      \foreach\i in {0,\h}
      {%
        \draw[line cap=round] (0,0,0.4\i) ++ (135:0.5) --++ (135:0.5);
        \draw[fill=white]     (0,0,0.4\i) ++ (135:1) circle (1pt);
      }
    \end{pgfonlayer}
  \end{scope}
}
\tikzset
{% styles for arrows and borders
  darrow/.style={% direct arrow
    decoration={markings,mark=at position 0.5 with {\arrow{latex}}},
    postaction={decorate}
    },
  rarrow/.style={% reverse arrow
    decoration={markings,mark=at position 0.5 with {\arrow{latex reversed}}},
    postaction={decorate}
    },
  wborder/.style={% white border
    preaction={draw,white,line width=2pt}
  }
}
\begin{document}
\begin{tikzpicture}[line cap=butt,x={(-\xx cm,-\xy cm)},y={(\xx cm,-\xy cm)},z={(0cm,\zz cm)}]
  % coils
  \mycoil{(0,0,0)}{5}{ 1}
  \mycoil{(0,0,6)}{4}{-1}
  \foreach\j in {0.1,0.3}
  {%
    \begin{scope}[rotate around z=135,canvas is xz plane at y=0]
      \draw[red,rarrow]         ( \j,0) arc  (180:225:0.5/\j-\j);
      \draw[red,wborder]        ( \j,0) --++ (0,8);
      \draw[red,wborder,darrow] ( \j,8) arc  (180:135:0.5/\j-\j);
      \draw[red,rarrow]         (-\j,0) arc  (0:-45:0.5/\j-\j);
      \draw[red,wborder]        (-\j,0) --++ (0,8);
      \draw[red,wborder,darrow] (-\j,8) arc  (0:45:0.5/\j-\j);
    \end{scope}
  }
  % labels
  \node[red] at (-1cm,-2cm)    {$\Phi$};
  \node      at (-1cm, 1cm)    {$N_2$};
  \node      at ( 1cm, 5.75cm) {$N_1$};
\end{tikzpicture}
\end{document}