Argthtjtr

I want to draw parallel arrows (for example 10 arrows) from a line to a curve. It is not good idea that dividing the line and curve to 10 parts and then join them to each other because of mathematical reason the resulting arrows are not parallel.

What I have done is the following.

documentclass{standalone}

usepackage{tikz}

usetikzlibrary{arrows,positioning}

begin{document}

begin{tikzpicture}[allow upside down]



draw  (0,0) circle (3.5);

draw (0,3.5) arc (90:-90:1.75 and 3.5) foreach p in {0,5,...,100} {

    node[inner sep=0cm,above,pos=p*0.01,

    anchor=center,

    minimum height=p*0.03cm,minimum width=(10+p)*0.3cm]

    (N p){}

};



draw (0,3.5) --(0,-3.5) foreach p in {0,5,...,100} {

    node[inner sep=0cm,above,pos=p*0.01,

    anchor=center,

    minimum height=p*0.03cm, minimum width=(10+p)*0.3cm]

    (M p){a}

};  



foreach p in {5,10,15,...,95} {

    draw[-latex,blue] (N p.center) -| (0,0);

}

end{tikzpicture}

end{document}

I do not really know if I understand what you want but a slight modification of your code produces "parallel arrows from a line to a curve".

documentclass[tikz,border=3.14mm]{standalone}

begin{document}

begin{tikzpicture}[allow upside down]



draw  (0,0) circle (3.5);

draw (0,3.5) arc (90:-90:1.75 and 3.5) foreach p in {0,5,...,100} {

    node[inner sep=0cm,above,pos=p*0.01,

    anchor=center,

    minimum height=p*0.03cm,minimum width=(10+p)*0.3cm]

    (N p){}

};

draw (0,3.5) -- (0,-3.5);



foreach p in {5,10,15,...,95} {

    draw[latex-,blue] (N p.center) -- (0,0 |- N p.center);

}

end{tikzpicture}

end{document}

ADDENDTUM: To reverse the arrows, you only need to replace draw[latex-,blue]... but draw[-latex,blue]. However, making the distance equal, requires slightly more effort

documentclass[tikz,border=3.14mm]{standalone}

usetikzlibrary{intersections}

begin{document}

begin{tikzpicture}[allow upside down]



draw  (0,0) circle (3.5);

draw[name path=arc] (0,3.5) arc (90:-90:1.75 and 3.5);

draw (0,3.5) -- (0,-3.5);



foreach p in {-3.25,-3,...,3.25} {

path[name path=line] (0,p) -- (3,p);

draw[latex-,blue,name intersections={of=line and arc}] 

(0,p) -- (intersection-1);

}

end{tikzpicture}

end{document}

You do not need intersections in this case, you could just use

documentclass[tikz,border=3.14mm]{standalone}

begin{document}

begin{tikzpicture}[allow upside down]



draw  (0,0) circle (3.5);

draw (0,3.5) arc (90:-90:1.75 and 3.5);

draw (0,3.5) -- (0,-3.5);



clip  (0,3.5) arc (90:-90:1.75 and 3.5) -- cycle;

foreach p in {-3.25,-3,...,3.25} {

draw[latex-,blue] 

(0,p) -- (3,p);

}

end{tikzpicture}

end{document}

A PSTricks solution only for fun purposes.

documentclass[pstricks]{standalone}

usepackage{pst-plot}



begin{document}

begin{pspicture}[algebraic](-4,-4)(4,4)

    pscircle{3}psline(0,-3)(0,3)

    psellipticarc(0,0)(1,3){-90}{90}

    curvepnodes[plotpoints=20]{-3}{3}{sqrt(1-(t/3)^2)|t}{A}

    foreach i in {1,...,numexprAnodecount-1}{pcline[nodesepB=.4pt]{<-}(0,0|Ai)(Ai)}

end{pspicture}

end{document}