TikZ: bad endpoint with "snake it" arc

Question

I'm trying to draw a simple diagram of the type showed in the picture below. I need an arc with a wiggle line. Using proper decoration packages, the option \draw [decorate,decoration=snake] does the wiggly line, but the endpoints of the arc are poorly done -- see the picture.

Here I link the code I'm currently using:

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\begin{document}
    
\begin{figure}
    \begin{center}
    \tikzpicture [scale=0.9, line width=0.30mm]
    \draw[decorate,decoration=snake](0.92,0) arc (0:180:0.92);
    \draw[dashed](-1.5,0)node[left]{$p$}--(1.5,0)node[right]{$-p'$};
    \draw[decorate,decoration={coil,amplitude=4pt, segment length=5pt}](0,1)--(0,2.2)node[above]{$k_0$};
    \endtikzpicture
    \end{center}
    \end{figure}

\end{document}

Does anyone know how to fix it? Thanks for the help!

Answer 1

You can draw the snake so it starts and ends well below the dashed line. Then clip is so only the part above the line appears:

It's unclear how you want the coil to attach.

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\begin{document}
    
\begin{figure}
    \begin{center}
    \tikzpicture [scale=0.9, line width=0.30mm]
    \begin{scope}
    \clip(-2,0)rectangle(2,2);
    \draw[decorate,decoration={snake}](-33:.92) arc (-33:210:.92);
    \end{scope}
    \draw[dashed](-1.5,0)node[left]{$p$}--(1.5,0)node[right]{$-p'$};
    \draw[decorate,decoration={coil,amplitude=4pt, segment length=5pt}](0,1)--(0,2.2)node[above]{$k_0$};
    \endtikzpicture
    \end{center}
\end{figure}

\end{document}