set logscale xy
set xrange[exp(-2.4):exp(1.0)]
set yrange[exp(-2.4):exp(2.0)]
set size square

set xlabel "a/v_A"
set ylabel "v/v_A"

p sqrt(0.5*(1+x**2+sqrt(1+2*(x**2)+x**4-4*(x**2)*1))) title "fast mode ({/Symbol q = 0{/Symbol\260})", sqrt(0.5*(1+x**2+sqrt(1+2*(x**2)+x**4-4*(x**2)*(3/4)))) title "fast mode ({/Symbol q = 30{/Symbol\260})", sqrt(0.5*(1+x**2+sqrt(1+2*(x**2)+x**4-4*(x**2)*(1/2)))) title "fast mode ({/Symbol q = 45{/Symbol\260})", sqrt(0.5*(1+x**2+sqrt(1+2*(x**2)+x**4-4*(x**2)*(1/4)))) title "fast mode ({/Symbol q = 60{/Symbol\260})"
replot sqrt(0.5*(1+x**2-sqrt(1+2*(x**2)+x**4-4*(x**2)*1))) title "slow mode ({/Symbol q = 0{/Symbol\260})", sqrt(0.5*(1+x**2-sqrt(1+2*(x**2)+x**4-4*(x**2)*(3/4)))) title "slow mode ({/Symbol q = 30{/Symbol\260})", sqrt(0.5*(1+x**2-sqrt(1+2*(x**2)+x**4-4*(x**2)*(1/2)))) title "slow mode ({/Symbol q = 45{/Symbol\260})", sqrt(0.5*(1+x**2-sqrt(1+2*(x**2)+x**4-4*(x**2)*(1/4)))) title "slow mode ({/Symbol q = 60{/Symbol\260})"

set terminal png
set output "DR1.png"
replot