tp4.tex

\begin{tikzpicture}[>=stealth]


	\def\r{.3};
	\def\M{1.5};

	% hp
	\draw (0,-.3) rectangle (.2,.3);
	\draw (.2,-.3) -- ++(.2,-.2) -- ++(0,1) -- ++(-.2,-.2);

	% wavefront
	\draw[->] (.8,0) -- ++(.7,0);
	\draw (1.1,-.2) -- ++(0,.4) node[above] {$\overrightarrow{k}$};
	\draw (1.2,-.2) -- ++(0,.4);

	% cylinder
	\draw (3,-2) rectangle (3+2*\r,3);
	\draw[dashed,<-] (3+\r,-4) node[right] {$z$} -- ++(0,8); % z axis
	\draw[dashed, ->] (4,0) -- ++(-2,0) node[above] {$x$};
	\draw[<->] (3+\r, 3.5) -- ++(\r,0) node[midway,above] {$a$};
	\draw[dashed] (3+2*\r,3) -- ++(0,.7);

	% absorbing material
	\draw[pattern=north east lines] (0,-3) rectangle (6,-2.5);
	\foreach \i in {1,...,20} \draw (\i*.3,-3) -- (.3*\i-.3,-3.2);



	% M point
	\draw (3+\r+\M,0) node {$\bullet$} node[above]  {$M$};

	% above-viewed
	\begin{scope}[shift={(7,0)}]
		% hp
		\draw (0,-.3) rectangle (.2,.3);
		\draw (.2,-.3) -- ++(.2,-.2) -- ++(0,1) -- ++(-.2,-.2);

		% wavefront
		\draw[->] (.8,0) -- ++(.7,0);
		\draw (1.1,-.2) -- ++(0,.4) node[above] {$\overrightarrow{k}$};
		\draw (1.2,-.2) -- ++(0,.4);

		\draw (3+\r,0) circle (\r);
		\draw[dashed,<-] (3+\r,-4) node[right] {$y$} -- (\r+3,2); % z axis
		\draw[dashed, ->] (4,0) -- ++(-2,0) node[near end, above] {$x$};

		% M point
		\draw[dotted, thick] (3+\r,0) circle (\M);
		\draw[dashed] (3+\r,0) -- ++(37:\M) node {$\bullet$} node[near end,left] {$r$} node[above] {$M$};



	\end{scope}

\end{tikzpicture}