set xrange [-6:6]
set yrange [-6:6]
set iso 12 # taille de la grille de points
set samp 12 # nombre de points utilisés
unset key
a = .0003
k = 9e9
Q = 1e-6
set object 1 circle front at 0,0 size 0.1 fillcolor rgb "black" lw 1
set arrow from -0.06,0 to 0.06,0 nohead
set arrow from 0,-0.07 to 0,0.07 nohead
plot '++' using 1:2:(a*k*Q*$1/($1**2+$2**2)**1.5):(a*k*Q*$2/($1**2+$2**2)**1.5)\
          w vec size .06, 15 filled
pause -1