7

I am trying to draw this kind of shape with arrows in LaTeX, but I am not able to do it using ellipse or any other shapes in tikz. Can anyone guide me how it can be drawn? enter image description here

10

The fact that these are not ovals has been nicely pointed out in this answer. The current answer is merely to point out that using pics and \foreach can help here.

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{arrows.meta,bending,decorations.markings}
\begin{document}
% from https://tex.stackexchange.com/a/430239/121799
\tikzset{% inspired by https://tex.stackexchange.com/a/316050/121799
    arc arrow/.style args={%
    to pos #1 with length #2}{
    decoration={
        markings,
         mark=at position 0 with {\pgfextra{%
         \pgfmathsetmacro{\tmpArrowTime}{#2/(\pgfdecoratedpathlength)}
         \xdef\tmpArrowTime{\tmpArrowTime}}},
        mark=at position {#1-\tmpArrowTime} with {\coordinate(@1);},
        mark=at position {#1-2*\tmpArrowTime/3} with {\coordinate(@2);},
        mark=at position {#1-\tmpArrowTime/3} with {\coordinate(@3);},
        mark=at position {#1} with {\coordinate(@4);
        \draw[-{Stealth[length=#2,bend]}]       
        (@1) .. controls (@2) and (@3) .. (@4);},
        },
     postaction=decorate,
     },
fixed arc arrow/.style={arc arrow=to pos #1 with length 3.14mm}     
}
\begin{tikzpicture}[pics/.cd,
not an oval/.style={code={
 \fill[#1!20] plot[smooth,variable=\x,domain=-1:1] ({\x},{0.75*cos(\x*180)+1.25})
 --
 plot[smooth,variable=\x,domain=1:-1] ({\x},{-0.75*cos(\x*180)-1.25}) -- cycle;
 \draw plot[smooth,variable=\x,domain=-1:1] ({\x},{0.75*cos(\x*180)+1.25})
 plot[smooth,variable=\x,domain=1:-1] ({\x},{-0.75*cos(\x*180)-1.25});
 \foreach \XX [count=\YY] in {0.5,0.6,0.7}
 {\draw[-latex,thick] (\XX,{-0.75*cos(\XX*180)-1.25})
    to[bend right=20+10*\YY] (-\XX,{-0.75*cos(\XX*180)-1.25}); 
  \draw[-latex,thick] (\XX,{0.75*cos(\XX*180)+1.25})
    to[bend left=20+10*\YY] (-\XX,{+0.75*cos(\XX*180)+1.25});}
 \draw[-latex,thick] (0.5,0) -- (-0.5,0);
 \draw[fill=#1] (0,0) circle (1mm);
}}]
 \edef\LstColors{{"blue","red"}}
 \path foreach \X in {1,...,7} {
 [/utils/exec={\pgfmathparse{\LstColors[mod(\X,2)]}
 \xdef\mycolor{\pgfmathresult}}]
 (2*\X,0)pic[xscale={-1*pow(-1,\X)}]{not an oval=\mycolor}};
 \draw[ultra thick,fixed arc arrow/.list={0.2,0.8},-{Stealth[length=3.14mm]}] 
 (0.8,0) arc(90:270:2) -- ++ (14.4,0)
 node[midway,above,scale=1.5]{$L=n\lambda_\mathrm{RF}+\lambda_\mathrm{RF}/2$} 
 node[midway,below]{$(\beta\sim1)$} 
 arc(-90:90:2);
 \draw[-{Stealth[length=3.14mm]},blue,ultra thick] (0.2,0) -- ++ (-2,0)
  node[midway,above]{$E_\mathrm{out}=E_\mathrm{inj}$};
 \draw[{Stealth[length=3.14mm]}-,red,ultra thick] (15.8,0) -- ++ (2,0)
 node[midway,above]{$E_\mathrm{in}=E_\mathrm{inj}$};
\end{tikzpicture}
\end{document}

enter image description here

EDIT: Moved the red arrow to the right (thanks to Sigur!) and also added a missing arrow head.

  • Amazing. Maybe move the red arrow a little bit to right to avoid overlapping with the black one. – Sigur Feb 19 at 17:47
  • It looks amazing. I really appreciate your effort and time for detailed answer. – Lauren Feb 19 at 19:34
  • @marmot I never seen the syntax @1, @2, ... What is it? The Tikz manual don't use @1 etc in examples (I searched the string "@1" in all files in /usr/local/texlive/2018/texmf-dist/doc/generic/pgf/text-en). Must I ask this in a new question? – quark67 Feb 20 at 5:06
  • 2
    @quark67 In this case it works as an ordinary letter would (in the sense you could replace it by X, say, and obtain the same result). That is, it is just a string here. I copied the practice from tex.stackexchange.com/a/316050/121799 and one reason why you may want to use it here is that it thus has a smaller chance to overwrite a named coordinate. Remember that coordinates in TikZ are global. – user121799 Feb 20 at 5:11
  • I didn't think we could use "@" as an ordinary letter. Thanks for the explanation! – quark67 Feb 20 at 5:16
6

Those aren't adjacent ovals! (There's actually no oval shapes in there!)

This is the area between sin(x)+a and -sin(x)-a. So, with the function plotting tools from pgf, you can draw function curves, and there's also flags to color the area below or above a curve, in an interval. That was probably done for alternating intervals of blue and red.

So, you'll need the pgfplot package, will make an axes area, draw the function plot, which you declared with something like

\pgfmathdeclarefunction{uppersine}{0}{\pgfmathparse{sin(x)+3}}
\pgfmathdeclarefunction{lowersine}{0}{\pgfmathparse{-sin(x)-3}}

and then draw the function:

\begin{tikzpicture}
  \begin{axis}[
    samples     = 1600,
    domain      = -0.2:20,
    xmin = -0.2, xmax = 20,
    ymin = -5, ymax = 5,
  ]
  \addplot[name path=top, line width=0.2pt, mark=none] {uppersine};
  \addplot[name path=bottom,  line width=0.2pt, mark=none] {lowersine};
  \addplot fill between[ 
    of = lowersine and uppersine, 
    split, % calculate segments
    style = {blue!70}
  ];
\end{axis}
\end{tikzpicture}

This code is very much adapted from this PGF example: enter image description here

As for the arrows: My guess is that you'd be happier than the original author if you also apply math to these and draw them as function plot rather than some line with uneven bend(?). An instruction on how to plot function plots with arrow heads can be found in this answer.

5

Another (not so short) answer:

\documentclass[tikz,margin=3mm]{standalone}
\usetikzlibrary{decorations.markings}
\def\toleft (#1,#2);{
    \fill[red!30] (#1-0.5,#2-0.25) rectangle (#1+0.5,#2+0.25);
    \path[draw=black,fill=red!30,postaction={
        decoration={
            markings,
            mark=at position 0.1 with \coordinate (a1-1);,
            mark=at position 0.175 with \coordinate (a2-1);,
            mark=at position 0.25 with \coordinate (a3-1);,
            mark=at position 0.9 with \coordinate (a1-2);,
            mark=at position 0.825 with \coordinate (a2-2);,
            mark=at position 0.75 with \coordinate (a3-2);
        },
        decorate
    }] (#1-0.5,#2+0.25) to[out=0,in=180] (#1,#2+1) to[out=0,in=180] (#1+0.5,#2+0.25);
    \draw[red!40] (#1-0.5,#2+0.25)--(#1+0.5,#2+0.25);
    \draw[<-] (a1-1) to[out=-60,in=-120] (a1-2);
    \draw[<-] (a2-1) to[out=-45,in=-135] (a2-2);
    \draw[<-] (a3-1) to[out=-35,in=-145] (a3-2);
    \path[draw=black,fill=red!30,postaction={
        decoration={
            markings,
            mark=at position 0.1 with \coordinate (b1-1);,
            mark=at position 0.175 with \coordinate (b2-1);,
            mark=at position 0.25 with \coordinate (b3-1);,
            mark=at position 0.9 with \coordinate (b1-2);,
            mark=at position 0.825 with \coordinate (b2-2);,
            mark=at position 0.75 with \coordinate (b3-2);
        },
        decorate
    }] (#1-0.5,#2-0.25) to[out=0,in=180] (#1,#2-1) to[out=0,in=180] (#1+0.5,#2-0.25);
    \draw[red!40] (#1-0.5,#2-0.25)--(#1+0.5,#2-0.25);
    \draw[<-] (b1-1) to[out=60,in=120] (b1-2);
    \draw[<-] (b2-1) to[out=45,in=135] (b2-2);
    \draw[<-] (b3-1) to[out=35,in=145] (b3-2);
    \draw[->] (#1+0.375,#2)--(#1-0.375,#2);
    \path[draw=black,fill=red] (#1,#2) circle (1pt);
}
\def\toright (#1,#2);{
    \fill[blue!30] (#1-0.5,#2-0.25) rectangle (#1+0.5,#2+0.25);
    \path[draw=black,fill=blue!30,postaction={
        decoration={
            markings,
            mark=at position 0.1 with \coordinate (a1-1);,
            mark=at position 0.175 with \coordinate (a2-1);,
            mark=at position 0.25 with \coordinate (a3-1);,
            mark=at position 0.9 with \coordinate (a1-2);,
            mark=at position 0.825 with \coordinate (a2-2);,
            mark=at position 0.75 with \coordinate (a3-2);
        },
        decorate
    }] (#1-0.5,#2+0.25) to[out=0,in=180] (#1,#2+1) to[out=0,in=180] (#1+0.5,#2+0.25);
    \draw[blue!40] (#1-0.5,#2+0.25)--(#1+0.5,#2+0.25);
    \draw[->] (a1-1) to[out=-60,in=-120] (a1-2);
    \draw[->] (a2-1) to[out=-45,in=-135] (a2-2);
    \draw[->] (a3-1) to[out=-35,in=-145] (a3-2);
    \path[draw=black,fill=blue!30,postaction={
        decoration={
            markings,
            mark=at position 0.1 with \coordinate (b1-1);,
            mark=at position 0.175 with \coordinate (b2-1);,
            mark=at position 0.25 with \coordinate (b3-1);,
            mark=at position 0.9 with \coordinate (b1-2);,
            mark=at position 0.825 with \coordinate (b2-2);,
            mark=at position 0.75 with \coordinate (b3-2);
        },
        decorate
    }] (#1-0.5,#2-0.25) to[out=0,in=180] (#1,#2-1) to[out=0,in=180] (#1+0.5,#2-0.25);
    \draw[blue!40] (#1-0.5,#2-0.25)--(#1+0.5,#2-0.25);
    \draw[->] (b1-1) to[out=60,in=120] (b1-2);
    \draw[->] (b2-1) to[out=45,in=135] (b2-2);
    \draw[->] (b3-1) to[out=35,in=145] (b3-2);
    \draw[<-] (#1+0.375,#2)--(#1-0.375,#2);
    \path[draw=black,fill=blue] (#1,#2) circle (1pt);
}
\begin{document}
\begin{tikzpicture}
\foreach \i in {-3,-1,1,3} \toleft (\i,0);
\foreach \i in {-2,0,2} \toright (\i,0);
\draw[very thick,->] (-3.75,0) arc (90:270:1cm);
\draw[very thick,<-] (3.75,0) arc (90:-90:1cm);
\draw[very thick,->] (-3.75,-2) node[above right] {$L=n\lambda_{RF}+\lambda_{RF}/2$}--(3.75,-2) node[above left] {$E=E_{\ln j}+\Delta E$} node[midway,below,font=\scriptsize] {$(\beta\sim1)$};
\draw[very thick,->,blue] (-4.25,0)--(-6,0) node[midway,above] {$E_\mathrm{out}=E_{\ln j}$};
\draw[very thick,->,red] (4.25,0)--(6,0) node[midway,above] {$E_{\ln j}$};
\end{tikzpicture}
\end{document}

enter image description here

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